Archive the Tricks: Ubuntu

Showing posts with label Ubuntu. Show all posts

Monday, July 11, 2011

How to install Drupal 7 on Ubuntu 11.4

To install Drupal 7, you have to install LAMP on you machine before. You can see my guide how to install LAMP on Ubuntu 11.4.
Ok. Now you got LAMP on your Ubuntu, we will install Drupal 7 in these steps below:

How to reset MySQL password!

Are you looking at this page because you cannot access the mysql server installed on your pc/server when you were trying to see if it works well? Or do you receive error messages like the following? :

ERROR 1045: Access denied for user: 'root@localhost' (Using
password: NO)

ERROR 1045: Access denied for user: 'root@localhost' (Using
password: YES)

To resolve this problem ,a fast and always working way is the "Password Resetting" .

How to install LAMP in Linux Ubuntu 11.04

How to install Linux, Apache, MySQL, PHP in Linux Ubuntu 11.4

I couldn't believe that it is so easy to install LAMP in Ubuntu. It is a little different with installing in older versions but steps are too easy to realize. Just do it now.
More Linux Tricks and How-tos can be found at: Linux Category.

1. Install Apache

How to Download, Install and Configure Komodo Edit

As I introduced in this blog before, in the title: Top 10 Linux/Unix HTML Editor
Komodo Edit and Komodo IDE is one of the best HTML Editor in Linux. They also have this software in Windows and MacOS editions. These editions also get high score. So today, I will show you how to download, install Komodo Edit - My favorite HTML Editor.

Linux / Unix Command: tar

NAME

tar - The GNU version of the tar archiving utility

SYNOPSIS

tar [ - ] A --catenate --concatenate | c --create | d --diff --compare | r --append | t --list | u --update | x -extract --get [ --atime-preserve ] [ -b, --block-size N ] [ -B, --read-full-blocks ] [ -C, --directory DIR ] [ --checkpoint ]
[ -f, --file [HOSTNAME:]F ] [ --force-local ]
[ -F, --info-script F --new-volume-script F ] [ -G, --incremental ] [ -g, --listed-incremental F ] [ -h, --dereference ] [ -i, --ignore-zeros ] [ -j, -I, --bzip ] [ --ignore-failed-read ] [ -k, --keep-old-files ] [ -K, --starting-file F ] [ -l, --one-file-system ] [ -L, --tape-length N ] [ -m, --modification-time ] [ -M, --multi-volume ] [ -N, --after-date DATE, --newer DATE ] [ -o, --old-archive, --portability ] [ -O, --to-stdout ] [ -p, --same-permissions, --preserve-permissions ] [ -P, --absolute-paths ] [ --preserve ]
[ -R, --record-number ] [ --remove-files ] [ -s, --same-order, --preserve-order ] [ --same-owner ] [ -S, --sparse ] [ -T, --files-from=F ] [ --null ]
[ --totals ]
[ -v, --verbose ] [ -V, --label NAME ] [ --version ]
[ -w, --interactive, --confirmation ] [ -W, --verify ]
[ --exclude FILE ] [ -X, --exclude-from FILE ] [ -Z, --compress, --uncompress ] [ -z, --gzip, --ungzip ]
[ --use-compress-program PROG ] [ --block-compress ] [ -[0-7][lmh] ]

filename1 [ filename2, ... filenameN ]
directory1 [ directory2, ...directoryN ]

DESCRIPTION

This manual page documents the GNU version of tar , an archiving program designed to store and extract files from an archive file known as a tarfile. A tarfile may be made on a tape drive, however, it is also common to write a tarfile to a normal file. The first argument to tar must be one of the options: Acdrtux, followed by any optional functions. The final arguments to tar are the names of the files or directories which should be archived. The use of a directory name always implies that the subdirectories below should be included in the archive.

FUNCTION LETTERS

One of the following options must be used:
-A, --catenate, --concatenate: append tar files to an archive
-c, --create: create a new archive
-d, --diff, --compare: find differences between archive and file system
--delete: delete from the archive (not for use on mag tapes!)
-r, --append: append files to the end of an archive
-t, --list: list the contents of an archive
-u, --update: only append files that are newer than copy in archive
-x, --extract, --get: extract files from an archive

OTHER OPTIONS

--atime-preserve: don't change access times on dumped files
-b, --block-size N: block size of Nx512 bytes (default N=20)
-B, --read-full-blocks: reblock as we read (for reading 4.2BSD pipes)
-C, --directory DIR: change to directory DIR
--checkpoint: print directory names while reading the archive
-f, --file [HOSTNAME:]F: use archive file or device F (default /dev/rmt0)
--force-local: archive file is local even if has a colon
-F, --info-script F --new-volume-script F: run script at end of each tape (implies -M)
-G, --incremental: create/list/extract old GNU-format incremental backup
-g, --listed-incremental F: create/list/extract new GNU-format incremental backup
-h, --dereference: don't dump symlinks; dump the files they point to
-i, --ignore-zeros: ignore blocks of zeros in archive (normally mean EOF)
-j, -I, --bzip: filter the archive through bzip2. Note: -I is deprecated and may get a different meaning in the near future.
--ignore-failed-read: don't exit with non-zero status on unreadable files
-k, --keep-old-files: keep existing files; don't overwrite them from archive
-K, --starting-file F: begin at file F in the archive
-l, --one-file-system: stay in local file system when creating an archive
-L, --tape-length N: change tapes after writing N*1024 bytes
-m, --modification-time: don't extract file modified time
-M, --multi-volume: create/list/extract multi-volume archive
-N, --after-date DATE, --newer DATE: only store files newer than DATE
-o, --old-archive, --portability: write a V7 format archive, rather than ANSI format
-O, --to-stdout: extract files to standard output
-p, --same-permissions, --preserve-permissions: extract all protection information
-P, --absolute-paths: don't strip leading `/'s from file names
--preserve: like -p -s
-R, --record-number: show record number within archive with each message
--remove-files: remove files after adding them to the archive
-s, --same-order, --preserve-order: list of names to extract is sorted to match archive
--same-owner: create extracted files with the same ownership
-S, --sparse: handle sparse files efficiently
-T, --files-from=F: get names to extract or create from file F
--null: -T reads null-terminated names, disable -C
--totals: print total bytes written with --create
-v, --verbose: verbosely list files processed
-V, --label NAME: create archive with volume name NAME
--version: print tar program version number
-w, --interactive, --confirmation: ask for confirmation for every action
-W, --verify: attempt to verify the archive after writing it
--exclude FILE: exclude file FILE
-X, --exclude-from FILE: exclude files listed in FILE
-Z, --compress, --uncompress: filter the archive through compress
-z, --gzip, --ungzip: filter the archive through gzip
--use-compress-program PROG: filter the archive through PROG (which must accept -d)

Important: Use the man command (% man) to see how a command is used on your particular computer.

Linux / Unix Command: less

NAME

less - opposite of more

EXAMPLES

SYNOPSIS

less -?
less --help
less -V
less --version
less [-[+]aBcCdeEfFgGiIJKmMnNqQrRsSuUVwWXZ~]
[-b space] [-h lines] [-j line] [-k keyfile]
[-K character set] [-{oO} logfile]
[-p pattern] [-P prompt] [-t tag]
[-T tagsfile] [-x tab,...] [-y lines] [-[z] lines]
[-# shift] [+[+]cmd] [--] [filename]...
(See the OPTIONS section for alternate option syntax with long option names.)

DESCRIPTION

Less is a program similar to more (1), but which allows backward movement in the file as well as forward movement. Also, less does not have to read the entire input file before starting, so with large input files it starts up faster than text editors like vi (1). Less uses termcap (or terminfo on some systems), so it can run on a variety of terminals. There is even limited support for hardcopy terminals. (On a hardcopy terminal, lines which should be printed at the top of the screen are prefixed with a caret.) Commands are based on both more and vi. Commands may be preceded by a decimal number, called N in the descriptions below. The number is used by some commands, as indicated.

COMMANDS

In the following descriptions, ^X means control-X. ESC stands for the ESCAPE key; for example ESC-v means the two character sequence "ESCAPE", then "v".

h or H

Help: display a summary of these commands. If you forget all the other commands, remember this one.

SPACE or ^V or f or ^F

Scroll forward N lines, default one window (see option -z below). If N is more than the screen size, only the final screenful is displayed. Warning: some systems use ^V as a special literalization character.

z

Like SPACE, but if N is specified, it becomes the new window size.

ESC-SPACE

Like SPACE, but scrolls a full screenful, even if it reaches end-of-file in the process.

RETURN or ^N or e or ^E or j or ^J

Scroll forward N lines, default 1. The entire N lines are displayed, even if N is more than the screen size.

d or ^D

Scroll forward N lines, default one half of the screen size. If N is specified, it becomes the new default for subsequent d and u commands.

b or ^B or ESC-v

Scroll backward N lines, default one window (see option -z below). If N is more than the screen size, only the final screenful is displayed.

w

Like ESC-v, but if N is specified, it becomes the new window size.

y or ^Y or ^P or k or ^K

Scroll backward N lines, default 1. The entire N lines are displayed, even if N is more than the screen size. Warning: some systems use ^Y as a special job control character.

u or ^U

Scroll backward N lines, default one half of the screen size. If N is specified, it becomes the new default for subsequent d and u commands.

ESC-) or RIGHTARROW

Scroll horizontally right N characters, default half the screen width (see the -# option). If a number N is specified, it becomes the default for future RIGHTARROW and LEFTARROW commands. While the text is scrolled, it acts as though the -S option (chop lines) were in effect.

ESC-( or LEFTARROW

Scroll horizontally left N characters, default half the screen width (see the -# option). If a number N is specified, it becomes the default for future RIGHTARROW and LEFTARROW commands.

r or ^R or ^L

Repaint the screen.

R

Repaint the screen, discarding any buffered input. Useful if the file is changing while it is being viewed.

F

Scroll forward, and keep trying to read when the end of file is reached. Normally this command would be used when already at the end of the file. It is a way to monitor the tail of a file which is growing while it is being viewed. (The behavior is similar to the "tail -f" command.)

g or < or ESC-<

Go to line N in the file, default 1 (beginning of file). (Warning: this may be slow if N is large.)

G or > or ESC->

Go to line N in the file, default the end of the file. (Warning: this may be slow if N is large, or if N is not specified and standard input, rather than a file, is being read.)

p or %

Go to a position N percent into the file. N should be between 0 and 100.

{

If a left curly bracket appears in the top line displayed on the screen, the { command will go to the matching right curly bracket. The matching right curly bracket is positioned on the bottom line of the screen. If there is more than one left curly bracket on the top line, a number N may be used to specify the N-th bracket on the line.

}

If a right curly bracket appears in the bottom line displayed on the screen, the } command will go to the matching left curly bracket. The matching left curly bracket is positioned on the top line of the screen. If there is more than one right curly bracket on the top line, a number N may be used to specify the N-th bracket on the line.

(

Like {, but applies to parentheses rather than curly brackets.

)

Like }, but applies to parentheses rather than curly brackets.

[

Like {, but applies to square brackets rather than curly brackets.

]

Like }, but applies to square brackets rather than curly brackets.

ESC-^F

Followed by two characters, acts like {, but uses the two characters as open and close brackets, respectively. For example, "ESC ^F < >" could be used to go forward to the > which matches the < in the top displayed line.

ESC-^B

Followed by two characters, acts like }, but uses the two characters as open and close brackets, respectively. For example, "ESC ^B < >" could be used to go backward to the < which matches the > in the bottom displayed line.

m

Followed by any lowercase letter, marks the current position with that letter.

'

(Single quote.) Followed by any lowercase letter, returns to the position which was previously marked with that letter. Followed by another single quote, returns to the position at which the last "large" movement command was executed. Followed by a ^ or $, jumps to the beginning or end of the file respectively. Marks are preserved when a new file is examined, so the ' command can be used to switch between input files.

^X^X

Same as single quote.

/pattern

Search forward in the file for the N-th line containing the pattern. N defaults to 1. The pattern is a regular expression, as recognized by ed. The search starts at the second line displayed (but see the -a and -j options, which change this). Certain characters are special if entered at the beginning of the pattern; they modify the type of search rather than become part of the pattern:

^N or !: Search for lines which do NOT match the pattern.
^E or *: Search multiple files. That is, if the search reaches the END of the current file without finding a match, the search continues in the next file in the command line list.
^F or @: Begin the search at the first line of the FIRST file in the command line list, regardless of what is currently displayed on the screen or the settings of the -a or -j options.
^K: Highlight any text which matches the pattern on the current screen, but don't move to the first match (KEEP current position).
^R: Don't interpret regular expression metacharacters; that is, do a simple textual comparison.

?pattern

Search backward in the file for the N-th line containing the pattern. The search starts at the line immediately before the top line displayed. Certain characters are special as in the / command:

^N or !: Search for lines which do NOT match the pattern.
^E or *: Search multiple files. That is, if the search reaches the beginning of the current file without finding a match, the search continues in the previous file in the command line list.
^F or @: Begin the search at the last line of the last file in the command line list, regardless of what is currently displayed on the screen or the settings of the -a or -j options.
^K: As in forward searches.
^R: As in forward searches.

ESC-/pattern

Same as "/*".

ESC-?pattern

Same as "?*".

n

Repeat previous search, for N-th line containing the last pattern. If the previous search was modified by ^N, the search is made for the N-th line NOT containing the pattern. If the previous search was modified by ^E, the search continues in the next (or previous) file if not satisfied in the current file. If the previous search was modified by ^R, the search is done without using regular expressions. There is no effect if the previous search was modified by ^F or ^K.

N

Repeat previous search, but in the reverse direction.

ESC-n

Repeat previous search, but crossing file boundaries. The effect is as if the previous search were modified by *.

ESC-N

Repeat previous search, but in the reverse direction and crossing file boundaries.

ESC-u

Undo search highlighting. Turn off highlighting of strings matching the current search pattern. If highlighting is already off because of a previous ESC-u command, turn highlighting back on. Any search command will also turn highlighting back on. (Highlighting can also be disabled by toggling the -G option; in that case search commands do not turn highlighting back on.)

:e [filename]

Examine a new file. If the filename is missing, the "current" file (see the :n and :p commands below) from the list of files in the command line is re-examined. A percent sign (%) in the filename is replaced by the name of the current file. A pound sign (#) is replaced by the name of the previously examined file. However, two consecutive percent signs are simply replaced with a single percent sign. This allows you to enter a filename that contains a percent sign in the name. Similarly, two consecutive pound signs are replaced with a single pound sign. The filename is inserted into the command line list of files so that it can be seen by subsequent :n and :p commands. If the filename consists of several files, they are all inserted into the list of files and the first one is examined. If the filename contains one or more spaces, the entire filename should be enclosed in double quotes (also see the -" option).

^X^V or E

Same as :e. Warning: some systems use ^V as a special literalization character. On such systems, you may not be able to use ^V.

:n

Examine the next file (from the list of files given in the command line). If a number N is specified, the N-th next file is examined.

:p

Examine the previous file in the command line list. If a number N is specified, the N-th previous file is examined.

:x

Examine the first file in the command line list. If a number N is specified, the N-th file in the list is examined.

:d

Remove the current file from the list of files.

t

Go to the next tag, if there were more than one matches for the current tag. See the -t option for more details about tags.

T

Go to the previous tag, if there were more than one matches for the current tag.

= or ^G or :f

Prints some information about the file being viewed, including its name and the line number and byte offset of the bottom line being displayed. If possible, it also prints the length of the file, the number of lines in the file and the percent of the file above the last displayed line.

@

Rotate the code recognition method of the current file. Enhanced less has 7 methods for recognition, default (which is chosen by the JLESSCHARSET environment variable), japanese, ujis, sjis, iso8, noconv and none.

-

Followed by one of the command line option letters (see OPTIONS below), this will change the setting of that option and print a message describing the new setting. If a ^P (CONTROL-P) is entered immediately after the dash, the setting of the option is changed but no message is printed. If the option letter has a numeric value (such as -b or -h), or a string value (such as -P or -t), a new value may be entered after the option letter. If no new value is entered, a message describing the current setting is printed and nothing is changed.

--

Like the - command, but takes a long option name (see OPTIONS below) rather than a single option letter. You must press RETURN after typing the option name. A ^P immediately after the second dash suppresses printing of a message describing the new setting, as in the - command.

-+

Followed by one of the command line option letters this will reset the option to its default setting and print a message describing the new setting. (The "-+X" command does the same thing as "-+X" on the command line.) This does not work for string-valued options.

--+

Like the -+ command, but takes a long option name rather than a single option letter.

-!

Followed by one of the command line option letters, this will reset the option to the "opposite" of its default setting and print a message describing the new setting. This does not work for numeric or string-valued options.

--!

Like the -! command, but takes a long option name rather than a single option letter.

_

(Underscore.) Followed by one of the command line option letters, this will print a message describing the current setting of that option. The setting of the option is not changed.

__

(Double underscore.) Like the _ (underscore) command, but takes a long option name rather than a single option letter. You must press RETURN after typing the option name.

+cmd

Causes the specified cmd to be executed each time a new file is examined. For example, +G causes less to initially display each file starting at the end rather than the beginning.

V

Prints the version number of less being run.

q or Q or :q or :Q or ZZ

Exits less.

The following four commands may or may not be valid, depending on your particular installation.

v: Invokes an editor to edit the current file being viewed. The editor is taken from the environment variable VISUAL if defined, or EDITOR if VISUAL is not defined, or defaults to "vi" if neither VISUAL nor EDITOR is defined. See also the discussion of LESSEDIT under the section on PROMPTS below.
! shell-command: Invokes a shell to run the shell-command given. A percent sign (%) in the command is replaced by the name of the current file. A pound sign (#) is replaced by the name of the previously examined file. "!!" repeats the last shell command. "!" with no shell command simply invokes a shell. On Unix systems, the shell is taken from the environment variable SHELL, or defaults to "sh". On MS-DOS and OS/2 systems, the shell is the normal command processor.
| <m> shell-command: <m> represents any mark letter. Pipes a section of the input file to the given shell command. The section of the file to be piped is between the first line on the current screen and the position marked by the letter. <m> may also be ^ or $ to indicate beginning or end of file respectively. If <m> is . or newline, the current screen is piped.
s filename: Save the input to a file. This only works if the input is a pipe, not an ordinary file.

OPTIONS

Command line options are described below. Most options may be changed while less is running, via the "-" command. Most options may be given in one of two forms: either a dash followed by a single letter, or two dashes followed by a long option name. A long option name may be abbreviated as long as the abbreviation is unambiguous. For example, --quit-at-eof may be abbreviated --quit, but not --qui, since both --quit-at-eof and --quiet begin with --qui. Some long option names are in uppercase, such as --QUIT-AT-EOF, as distinct from --quit-at-eof. Such option names need only have their first letter capitalized; the remainder of the name may be in either case. For example, --Quit-at-eof is equivalent to --QUIT-AT-EOF.
Options are also taken from the environment variable "LESS" and "JLESS". For example, to avoid typing "less -options ..." each time less is invoked, you might tell csh:
setenv LESS "-options"
or if you use sh:
LESS="-options"; export LESS
On MS-DOS, you don't need the quotes, but you should replace any percent signs in the options string by double percent signs.
The environment variable is parsed before the command line, so command line options override the LESS and JLESS environment variables. If an option appears in the LESS and JLESS variables, it can be reset to its default value on the command line by beginning the command line option with "-+".
For options like -P or -D which take a following string, a dollar sign ($) must be used to signal the end of the string. For example, to set two -D options on MS-DOS, you must have a dollar sign between them, like this:
LESS="-Dn9.1$-Ds4.1"

-? or --help: This option displays a summary of the commands accepted by less (the same as the h command). (Depending on how your shell interprets the question mark, it may be necessary to quote the question mark, thus: "-\?".)
-a or --search-skip-screen: Causes searches to start after the last line displayed on the screen, thus skipping all lines displayed on the screen. By default, searches start at the second line on the screen (or after the last found line; see the -j option).
-bn or --buffers=n: Specifies the amount of buffer space less will use for each file, in units of kilobytes (1024 bytes). By default 64K of buffer space is used for each file (unless the file is a pipe; see the -B option). The -b option specifies instead that n kilobytes of buffer space should be used for each file. If n is -1, buffer space is unlimited; that is, the entire file is read into memory.
-B or --auto-buffers: By default, when data is read from a pipe, buffers are allocated automatically as needed. If a large amount of data is read from the pipe, this can cause a large amount of memory to be allocated. The -B option disables this automatic allocation of buffers for pipes, so that only 64K (or the amount of space specified by the -b option) is used for the pipe. Warning: use of -B can result in erroneous display, since only the most recently viewed part of the file is kept in memory; any earlier data is lost.
-c or --clear-screen: Causes full screen repaints to be painted from the top line down. By default, full screen repaints are done by scrolling from the bottom of the screen.
-C or --CLEAR-SCREEN: The -C option is like -c, but the screen is cleared before it is repainted.
-d or --dumb: The -d option suppresses the error message normally displayed if the terminal is dumb; that is, lacks some important capability, such as the ability to clear the screen or scroll backward. The -d option does not otherwise change the behavior of less on a dumb terminal.
-Dxcolor or --color=xcolor: [MS-DOS only] Sets the color of the text displayed. x is a single character which selects the type of text whose color is being set: n=normal, s=standout, d=bold, u=underlined, k=blink. color is a pair of numbers separated by a period. The first number selects the foreground color and the second selects the background color of the text. A single number N is the same as N.0.
-e or --quit-at-eof: Causes less to automatically exit the second time it reaches end-of-file. By default, the only way to exit less is via the "q" command.
-E or --QUIT-AT-EOF: Causes less to automatically exit the first time it reaches end-of-file.
-f or --force: Forces non-regular files to be opened. (A non-regular file is a directory or a device special file.) Also suppresses the warning message when a binary file is opened. By default, less will refuse to open non-regular files.
-F or --quit-if-one-screen: Causes less to automatically exit if the entire file can be displayed on the first screen.
-g or --hilite-search: Normally, less will highlight ALL strings which match the last search command. The -g option changes this behavior to highlight only the particular string which was found by the last search command. This can cause less to run somewhat faster than the default.
-G or --HILITE-SEARCH: The -G option suppresses all highlighting of strings found by search commands.
-hn or ---max-back-scroll=n: Specifies a maximum number of lines to scroll backward. If it is necessary to scroll backward more than n lines, the screen is repainted in a forward direction instead. (If the terminal does not have the ability to scroll backward, -h0 is implied.)
-i or --ignore-case: Causes searches to ignore case; that is, uppercase and lowercase are considered identical. This option is ignored if any uppercase letters appear in the search pattern; in other words, if a pattern contains uppercase letters, then that search does not ignore case.
-I or --IGNORE-CASE: Like -i, but searches ignore case even if the pattern contains uppercase letters.
-jn or --jump-target=n: Specifies a line on the screen where the "target" line is to be positioned. A target line is the object of a text search, tag search, jump to a line number, jump to a file percentage, or jump to a marked position. The screen line is specified by a number: the top line on the screen is 1, the next is 2, and so on. The number may be negative to specify a line relative to the bottom of the screen: the bottom line on the screen is -1, the second to the bottom is -2, and so on. If the -j option is used, searches begin at the line immediately after the target line. For example, if "-j4" is used, the target line is the fourth line on the screen, so searches begin at the fifth line on the screen.
-J or --status-column: Displays a status column at the left edge of the screen. The status column shows the lines that matched the current search. The status column is also used if the -w or -W option is in effect.
-kfilename or --lesskey-file=filename: Causes less to open and interpret the named file as a lesskey (1) file. Multiple -k options may be specified. If the LESSKEY or LESSKEY_SYSTEM environment variable is set, or if a lesskey file is found in a standard place (see KEY BINDINGS), it is also used as a lesskey file.
-Kcharset: Causes less to use this charset instead of a charset defined in the JLESSCHARSET or LESSCHARSET environment variable.
-m or --long-prompt: Causes less to prompt verbosely (like more), with the percent into the file. By default, less prompts with a colon.
-M or --LONG-PROMPT: Causes less to prompt even more verbosely than more.
-n or --line-numbers: Suppresses line numbers. The default (to use line numbers) may cause less to run more slowly in some cases, especially with a very large input file. Suppressing line numbers with the -n option will avoid this problem. Using line numbers means: the line number will be displayed in the verbose prompt and in the = command, and the v command will pass the current line number to the editor (see also the discussion of LESSEDIT in PROMPTS below).
-N or --LINE-NUMBERS: Causes a line number to be displayed at the beginning of each line in the display.
-ofilename or --log-file=filename: Causes less to copy its input to the named file as it is being viewed. This applies only when the input file is a pipe, not an ordinary file. If the file already exists, less will ask for confirmation before overwriting it.
-Ofilename or --LOG-FILE=filename: The -O option is like -o, but it will overwrite an existing file without asking for confirmation. If no log file has been specified, the -o and -O options can be used from within less to specify a log file. Without a file name, they will simply report the name of the log file. The "s" command is equivalent to specifying -o from within less.
-ppattern or --pattern=pattern: The -p option on the command line is equivalent to specifying +/pattern; that is, it tells less to start at the first occurrence of pattern in the file.
-Pprompt or --prompt=prompt: Provides a way to tailor the three prompt styles to your own preference. This option would normally be put in the LESS and JLESS environment variables, rather than being typed in with each less command. Such an option must either be the last option in the LESS and JLESS variables, or be terminated by a dollar sign. -Ps followed by a string changes the default (short) prompt to that string. -Pm changes the medium (-m) prompt. -PM changes the long (-M) prompt. -Ph changes the prompt for the help screen. -P= changes the message printed by the = command. -Pw changes the message printed while waiting for data (in the F command). All prompt strings consist of a sequence of letters and special escape sequences. See the section on PROMPTS for more details.
-q or --quiet or --silent: Causes moderately "quiet" operation: the terminal bell is not rung if an attempt is made to scroll past the end of the file or before the beginning of the file. If the terminal has a "visual bell", it is used instead. The bell will be rung on certain other errors, such as typing an invalid character. The default is to ring the terminal bell in all such cases.
-Q or --QUIET or --SILENT: Causes totally "quiet" operation: the terminal bell is never rung.
-r or --raw-control-chars: Causes "raw" control characters to be displayed. The default is to display control characters using the caret notation; for example, a control-A (octal 001) is displayed as "^A". Warning: when the -r option is used, less cannot keep track of the actual appearance of the screen (since this depends on how the screen responds to each type of control character). Thus, various display problems may result, such as long lines being split in the wrong place.
-R or --RAW-CONTROL-CHARS: Like -r, but tries to keep track of the screen appearance where possible. This works only if the input consists of normal text and possibly some ANSI "color" escape sequences, which are sequences of the form: ESC [ ... m where the "..." is zero or more characters other than "m". For the purpose of keeping track of screen appearance, all control characters and all ANSI color escape sequences are assumed to not move the cursor. You can make less think that characters other than "m" can end ANSI color escape sequences by setting the environment variable LESSANSIENDCHARS to the list of characters which can end a color escape sequence.
-s or --squeeze-blank-lines: Causes consecutive blank lines to be squeezed into a single blank line. This is useful when viewing nroff output.
-S or --chop-long-lines: Causes lines longer than the screen width to be chopped rather than folded. That is, the remainder of a long line is simply discarded. The default is to fold long lines; that is, display the remainder on the next line.
-ttag or --tag=tag: The -t option, followed immediately by a TAG, will edit the file containing that tag. For this to work, tag information must be available; for example, there may be a file in the current directory called "tags", which was previously built by ctags (1) or an equivalent command. If the environment variable LESSGLOBALTAGS is set, it is taken to be the name of a command compatible with global (1), and that command is executed to find the tag. (See http://www.gnu.org/software/global/global.html). The -t option may also be specified from within less (using the - command) as a way of examining a new file. The command ":t" is equivalent to specifying -t from within less.
-Ttagsfile or --tag-file=tagsfile: Specifies a tags file to be used instead of "tags".
-u or --underline-special: Causes backspaces and carriage returns to be treated as printable characters; that is, they are sent to the terminal when they appear in the input.
-U or --UNDERLINE-SPECIAL: Causes backspaces, tabs and carriage returns to be treated as control characters; that is, they are handled as specified by the -r option. By default, if neither -u nor -U is given, backspaces which appear adjacent to an underscore character are treated specially: the underlined text is displayed using the terminal's hardware underlining capability. Also, backspaces which appear between two identical characters are treated specially: the overstruck text is printed using the terminal's hardware boldface capability. Other backspaces are deleted, along with the preceding character. Carriage returns immediately followed by a newline are deleted. other carriage returns are handled as specified by the -r option. Text which is overstruck or underlined can be searched for if neither -u nor -U is in effect.
-V or --version: Displays the version number of less.
-w or --hilite-unread: Temporarily highlights the first "new" line after a forward movement of a full page. The first "new" line is the line immediately following the line previously at the bottom of the screen. Also highlights the target line after a g or p command. The highlight is removed at the next command which causes movement. The entire line is highlighted, unless the -J option is in effect, in which case only the status column is highlighted.
-W or --HILITE-UNREAD: Like -w, but temporarily highlights the first new line after any forward movement command larger than one line.
-xn,... or --tabs=n,...: Sets tab stops. If only one n is specified, tab stops are set at multiples of n. If multiple values separated by commas are specified, tab stops are set at those positions, and then continue with the same spacing as the last two. For example, -x9,17 will set tabs at positions 9, 17, 25, 33, etc. The default for n is 8.
-X or --no-init: Disables sending the termcap initialization and deinitialization strings to the terminal. This is sometimes desirable if the deinitialization string does something unnecessary, like clearing the screen.
--no-keypad: Disables sending the keypad initialization and deinitialization strings to the terminal. This is sometimes useful if the keypad strings make the numeric keypad behave in an undesirable manner.
-yn or --max-forw-scroll=n: Specifies a maximum number of lines to scroll forward. If it is necessary to scroll forward more than n lines, the screen is repainted instead. The -c or -C option may be used to repaint from the top of the screen if desired. By default, any forward movement causes scrolling.
-[z]n or --window=n: Changes the default scrolling window size to n lines. The default is one screenful. The z and w commands can also be used to change the window size. The "z" may be omitted for compatibility with more. If the number n is negative, it indicates n lines less than the current screen size. For example, if the screen is 24 lines, -z-4 sets the scrolling window to 20 lines. If the screen is resized to 40 lines, the scrolling window automatically changes to 36 lines.
-Z: Causes to give priority to the SJIS over the UJIS if a "japanese" was selected by the JLESSCHARSET environment variable. The default value is to give priority to the UJIS over the SJIS.
-dqcc or --quotes=cc: Changes the filename quoting character. This may be necessary if you are trying to name a file which contains both spaces and quote characters. Followed by a single character, this changes the quote character to that character. Filenames containing a space should then be surrounded by that character rather than by double quotes. Followed by two characters, changes the open quote to the first character, and the close quote to the second character. Filenames containing a space should then be preceded by the open quote character and followed by the close quote character. Note that even after the quote characters are changed, this option remains -" (a dash followed by a double quote).
-~ or --tilde: Normally lines after end of file are displayed as a single tilde (~). This option causes lines after end of file to be displayed as blank lines.
-# or --shift: Specifies the default number of positions to scroll horizontally in the RIGHTARROW and LEFTARROW commands. If the number specified is zero, it sets the default number of positions to one half of the screen width.
--: A command line argument of "--" marks the end of option arguments. Any arguments following this are interpreted as filenames. This can be useful when viewing a file whose name begins with a "-" or "+".
+: If a command line option begins with +, the remainder of that option is taken to be an initial command to less. For example, +G tells less to start at the end of the file rather than the beginning, and +/xyz tells it to start at the first occurrence of "xyz" in the file. As a special case, +<number> acts like +<number>g; that is, it starts the display at the specified line number (however, see the caveat under the "g" command above). If the option starts with ++, the initial command applies to every file being viewed, not just the first one. The + command described previously may also be used to set (or change) an initial command for every file.

LINE EDITING

When entering command line at the bottom of the screen (for example, a filename for the :e command, or the pattern for a search command), certain keys can be used to manipulate the command line. Most commands have an alternate form in [ brackets ] which can be used if a key does not exist on a particular keyboard. (The bracketed forms do not work in the MS-DOS version.) Any of these special keys may be entered literally by preceding it with the "literal" character, either ^V or ^A. A backslash itself may also be entered literally by entering two backslashes.

LEFTARROW [ ESC-h ]: Move the cursor one space to the left.
RIGHTARROW [ ESC-l ]: Move the cursor one space to the right.
^LEFTARROW [ ESC-b or ESC-LEFTARROW ]: (That is, CONTROL and LEFTARROW simultaneously.) Move the cursor one word to the left.
^RIGHTARROW [ ESC-w or ESC-RIGHTARROW ]: (That is, CONTROL and RIGHTARROW simultaneously.) Move the cursor one word to the right.
HOME [ ESC-0 ]: Move the cursor to the beginning of the line.
END [ ESC-$ ]: Move the cursor to the end of the line.
BACKSPACE: Delete the character to the left of the cursor, or cancel the command if the command line is empty.
DELETE or [ ESC-x ]: Delete the character under the cursor.
^BACKSPACE [ ESC-BACKSPACE ]: (That is, CONTROL and BACKSPACE simultaneously.) Delete the word to the left of the cursor.
^DELETE [ ESC-X or ESC-DELETE ]: (That is, CONTROL and DELETE simultaneously.) Delete the word under the cursor.
UPARROW [ ESC-k ]: Retrieve the previous command line.
DOWNARROW [ ESC-j ]: Retrieve the next command line.
TAB: Complete the partial filename to the left of the cursor. If it matches more than one filename, the first match is entered into the command line. Repeated TABs will cycle thru the other matching filenames. If the completed filename is a directory, a "/" is appended to the filename. (On MS-DOS systems, a "\" is appended.) The environment variable LESSSEPARATOR can be used to specify a different character to append to a directory name.
BACKTAB [ ESC-TAB ]: Like, TAB, but cycles in the reverse direction thru the matching filenames.
^L: Complete the partial filename to the left of the cursor. If it matches more than one filename, all matches are entered into the command line (if they fit).
^U (Unix and OS/2) or ESC (MS-DOS): Delete the entire command line, or cancel the command if the command line is empty. If you have changed your line-kill character in Unix to something other than ^U, that character is used instead of ^U.

KEY BINDINGS

You may define your own less commands by using the program lesskey (1) to create a lesskey file. This file specifies a set of command keys and an action associated with each key. You may also use lesskey to change the line-editing keys (see LINE EDITING), and to set environment variables. If the environment variable LESSKEY is set, less uses that as the name of the lesskey file. Otherwise, less looks in a standard place for the lesskey file: On Unix systems, less looks for a lesskey file called "$HOME/.less". On MS-DOS and Windows systems, less looks for a lesskey file called "$HOME/_less", and if it is not found there, then looks for a lesskey file called "_less" in any directory specified in the PATH environment variable. On OS/2 systems, less looks for a lesskey file called "$HOME/less.ini", and if it is not found, then looks for a lesskey file called "less.ini" in any directory specified in the INIT environment variable, and if it not found there, then looks for a lesskey file called "less.ini" in any directory specified in the PATH environment variable. See the lesskey manual page for more details. A system-wide lesskey file may also be set up to provide key bindings. If a key is defined in both a local lesskey file and in the system-wide file, key bindings in the local file take precedence over those in the system-wide file. If the environment variable LESSKEY_SYSTEM is set, less uses that as the name of the system-wide lesskey file. Otherwise, less looks in a standard place for the system-wide lesskey file: On Unix systems, the system-wide lesskey file is /usr/local/etc/sysless. (However, if less was built with a different sysconf directory than /usr/local/etc, that directory is where the sysless file is found.) On MS-DOS and Windows systems, the system-wide lesskey file is c:\_sysless. On OS/2 systems, the system-wide lesskey file is c:\sysless.ini.

INPUT PREPROCESSOR

You may define an "input preprocessor" for less. Before less opens a file, it first gives your input preprocessor a chance to modify the way the contents of the file are displayed. An input preprocessor is simply an executable program (or shell script), which writes the contents of the file to a different file, called the replacement file. The contents of the replacement file are then displayed in place of the contents of the original file. However, it will appear to the user as if the original file is opened; that is, less will display the original filename as the name of the current file. An input preprocessor receives one command line argument, the original filename, as entered by the user. It should create the replacement file, and when finished, print the name of the replacement file to its standard output. If the input preprocessor does not output a replacement filename, less uses the original file, as normal. The input preprocessor is not called when viewing standard input. To set up an input preprocessor, set the LESSOPEN environment variable to a command line which will invoke your input preprocessor. This command line should include one occurrence of the string "%s", which will be replaced by the filename when the input preprocessor command is invoked.
When less closes a file opened in such a way, it will call another program, called the input postprocessor, which may perform any desired clean-up action (such as deleting the replacement file created by LESSOPEN). This program receives two command line arguments, the original filename as entered by the user, and the name of the replacement file. To set up an input postprocessor, set the LESSCLOSE environment variable to a command line which will invoke your input postprocessor. It may include two occurrences of the string "%s"; the first is replaced with the original name of the file and the second with the name of the replacement file, which was output by LESSOPEN.
For example, on many Unix systems, these two scripts will allow you to keep files in compressed format, but still let less view them directly:
lessopen.sh:
#! /bin/sh

case "$1" in

*.Z) uncompress -c $1 >/tmp/less.$$ 2>/dev/null

if [ -s /tmp/less.$$ ]; then

echo /tmp/less.$$

else

rm -f /tmp/less.$$

fi

;;

esac
lessclose.sh:
#! /bin/sh

rm $2
To use these scripts, put them both where they can be executed and set LESSOPEN="lessopen.sh %s", and LESSCLOSE="lessclose.sh %s %s". More complex LESSOPEN and LESSCLOSE scripts may be written to accept other types of compressed files, and so on.
It is also possible to set up an input preprocessor to pipe the file data directly to less, rather than putting the data into a replacement file. This avoids the need to decompress the entire file before starting to view it. An input preprocessor that works this way is called an input pipe. An input pipe, instead of writing the name of a replacement file on its standard output, writes the entire contents of the replacement file on its standard output. If the input pipe does not write any characters on its standard output, then there is no replacement file and less uses the original file, as normal. To use an input pipe, make the first character in the LESSOPEN environment variable a vertical bar (|) to signify that the input preprocessor is an input pipe.
For example, on many Unix systems, this script will work like the previous example scripts:
lesspipe.sh:
#! /bin/sh

case "$1" in

*.Z) uncompress -c $1 2>/dev/null

;;

esac

To use this script, put it where it can be executed and set LESSOPEN="|lesspipe.sh %s". When an input pipe is used, a LESSCLOSE postprocessor can be used, but it is usually not necessary since there is no replacement file to clean up. In this case, the replacement file name passed to the LESSCLOSE postprocessor is "-".

NATIONAL CHARACTER SETS

There are three types of characters in the input file:

normal characters: can be displayed directly to the screen.
control characters: should not be displayed directly, but are expected to be found in ordinary text files (such as backspace and tab).
binary characters: should not be displayed directly and are not expected to be found in text files.

A "character set" is simply a description of which characters are to be considered normal, control, and binary. The JLESSCHARSET and LESSCHARSET environment variables may be used to select a character set. There is no difference between them in program of less. But I suppose you should use the JLESSCHARSET environment variable because not enhanced less will make errors if you use enhanced character set in your LESSCHARSET environment variable. Possible values for them are:

ascii: BS, TAB, NL, CR, and formfeed are control characters, all chars with values between 32 and 126 are normal, and all others are binary.
iso8859: Selects an ISO 8859 character set. This is the same as ASCII, except characters between 160 and 255 are treated as normal characters.
latin1: Same as iso8859.
latin9: Same as iso8859.
dos: Selects a character set appropriate for MS-DOS.
ebcdic: Selects an EBCDIC character set.
IBM-1047: Selects an EBCDIC character set used by OS/390 Unix Services. This is the EBCDIC analogue of latin1. You get similar results by setting either LESSCHARSET=IBM-1047 or LC_CTYPE=en_US in your environment.
koi8-r: Selects a Russian character set.
next: Selects a character set appropriate for NeXT computers.
utf-8: Selects the UTF-8 encoding of the ISO 10646 character set.

Possible values for only JLESSCHARSET are:

iso7: Multi character sets with the ISO 2022 code extension techniques in 7 bits are assumed. Characters with values between 128 and 255 are treated as binary. The level of implementation of Less is level 3 of ISO 2022.
iso8: Multi character sets with the ISO 2022 code extension techniques in 8 bits are assumed. The level of implementation of Less is level 3 of ISO 2022.
jis: Only Japanese character sets with the ISO 2022 code extension techniques in 7 bits are assumed.
ujis: If characters has values between 32 and 127, the ASCII character set are assumed. If characters has values between 162 and 254, the JISX 0208 character set, a right half of the JISX 0201 character set and the JISX 0212 character set with the UJIS coding are assumed. Otherwise, characters are treated as binary.
euc: Same as ujis.
sjis: If characters has values between 32 and 127, the ASCII character set are assumed. If characters has values between 128 and 252, the JISX 0208 character set and a right half of the JISX 0201 character set are assumed. Otherwise, characters are treated as binary.
japanese: All Japanese character sets, jis, ujis and sjis, are assumed. But less output only the jis.

Japanese has several code sets (not character sets). Thus less must convert among them to display them correctly. Possible values with this conversion for only JLESSCHARSET are:

ujis-iso7: The ujis and iso7 are assumend. But less output only the iso7.
euc-iso7: Same as ujis-iso7.
sjis-iso7: The sjis and iso7 are assumend. But less output only the iso7.
ujis-jis: The ujis and jis are assumend. But less output only the jis.
euc-jis: Same as ujis-jis.
sjis-jis: The sjis and jis are assumend. But less output only the jis.
jis-ujis: The jis and ujis are assumend. But less output only the ujis.
jis-euc: Same as jis-ujis.
jis-sjis: The jis and sjis are assumend. But less output only the sjis.
japanese-iso7: The japanese and iso7 are assumend. But less output only the iso7.
japanese-jis: The japanese is assumend. But less output only the jis. Same as japanese.
japanese-ujis: The japanese is assumend. But less output only the ujis.
japanese-euc: Same as japanese-ujis.
japanese-sjis: The japanese is assumend. But less output only the sjis.
ujis-sjis: The ujis is assumend. But less output only the sjis.
euc-sjis: Same as ujis-sjis.
sjis-ujis: The sjis is assumend. But less output only the ujis.
sjis-euc: Same as sjis-ujis.

Other way to select a character set is to use the LANG environment variable. If it start with "ja_JP" or "japan", less read all Japanese coded characters as some Japanese character set, and a rest of the LANG environment variable specify output coding.
The ISO 2022 code extension techniques define 4 planes to display many character sets easy. Default setting of planes is selected by the JLESSPLANESET environment variable. If the JLESSPLANESET vriable is equal to "japanese", "ujis" or "euc", less treat g1 plane as JISX 0208, g2 plane as JISX 0201 right half, g3 plane as JISX 0212. If it is equal to "latin1", "latin2", "latin3", "latin4", "greek", "alabic", "hebrew", "cyrillic" or "latin5", less treat g1 plane as one of ISO 8859. Otherwise, less try to parse the JLESSPLANESET variable as real escape sequences for setting up, and "\e" in JLESSPLANESET is treated as escape code when parsing.
Less understand almost all escape sequence about character set in the ISO 2022 code extension techniques. There are many escape sequences to select the character set. On the one hand, less output only 6 escape sequences to select a character set: '^[(', '^[-', '^[$(', '^[$-', '^N' and '^O'. It means less is friendly to a terminal and a terminal emulator.
And there is special "character set" for keyboard inputs. The JLESSKEYCHARSET environment variable is used for such purpose. Possible values of it are equal to the JLESSCHARSET environment variable.
In special cases, it may be desired to tailor less to use a character set other than the ones definable by LESSCHARSET. In this case, the environment variable LESSCHARDEF can be used to define a character set. It should be set to a string where each character in the string represents one character in the character set. The character "." is used for a normal character, "c" for control, and "b" for binary. A decimal number may be used for repetition. For example, "bccc4b." would mean character 0 is binary, 1, 2 and 3 are control, 4, 5, 6 and 7 are binary, and 8 is normal. All characters after the last are taken to be the same as the last, so characters 9 through 255 would be normal. (This is an example, and does not necessarily represent any real character set.)
This table shows the value of LESSCHARDEF which is equivalent to each of the possible values for LESSCHARSET:
ascii 8bcccbcc18b95.b

dos 8bcccbcc12bc5b95.b.

ebcdic 5bc6bcc7bcc41b.9b7.9b5.b..8b6.10b6.b9.7b

9.8b8.17b3.3b9.7b9.8b8.6b10.b.b.b.

IBM-1047 4cbcbc3b9cbccbccbb4c6bcc5b3cbbc4bc4bccbc
191.b

iso8859 8bcccbcc18b95.33b.

koi8-r 8bcccbcc18b95.b128.

latin1 8bcccbcc18b95.33b.

next 8bcccbcc18b95.bb125.bb
If neither LESSCHARSET nor LESSCHARDEF is set, but the string "UTF-8" is found in the LC_ALL, LC_TYPE or LANG environment variables, then the default character set is utf-8.
If that string is not found, but your system supports the setlocale interface, less will use setlocale to determine the character set. setlocale is controlled by setting the LANG or LC_CTYPE environment variables.
Finally, if the setlocale interface is also not available, the default character set is latin1.
Control and binary characters are displayed in standout (reverse video). Each such character is displayed in caret notation if possible (e.g. ^A for control-A). Caret notation is used only if inverting the 0100 bit results in a normal printable character. Otherwise, the character is displayed as a hex number in angle brackets. This format can be changed by setting the LESSBINFMT environment variable. LESSBINFMT may begin with a "*" and one character to select the display attribute: "*k" is blinking, "*d" is bold, "*u" is underlined, "*s" is standout, and "*n" is normal. If LESSBINFMT does not begin with a "*", normal attribute is assumed. The remainder of LESSBINFMT is a string which may include one printf-style escape sequence (a % followed by x, X, o, d, etc.). For example, if LESSBINFMT is "*u[%x]", binary characters are displayed in underlined hexadecimal surrounded by brackets. The default if no LESSBINFMT is specified is "*s<%X>".

PROMPTS

The -P option allows you to tailor the prompt to your preference. The string given to the -P option replaces the specified prompt string. Certain characters in the string are interpreted specially. The prompt mechanism is rather complicated to provide flexibility, but the ordinary user need not understand the details of constructing personalized prompt strings. A percent sign followed by a single character is expanded according to what the following character is:

%bX: Replaced by the byte offset into the current input file. The b is followed by a single character (shown as X above) which specifies the line whose byte offset is to be used. If the character is a "t", the byte offset of the top line in the display is used, an "m" means use the middle line, a "b" means use the bottom line, a "B" means use the line just after the bottom line, and a "j" means use the "target" line, as specified by the -j option.
%B: Replaced by the size of the current input file.
%c: Replaced by the column number of the text appearing in the first column of the screen.
%dX: Replaced by the page number of a line in the input file. The line to be used is determined by the X, as with the %b option.
%D: Replaced by the number of pages in the input file, or equivalently, the page number of the last line in the input file.
%E: Replaced by the name of the editor (from the VISUAL environment variable, or the EDITOR environment variable if VISUAL is not defined). See the discussion of the LESSEDIT feature below.
%f: Replaced by the name of the current input file.
%i: Replaced by the index of the current file in the list of input files.
%lX: Replaced by the line number of a line in the input file. The line to be used is determined by the X, as with the %b option.
%L: Replaced by the line number of the last line in the input file.
%m: Replaced by the total number of input files.
%pX: Replaced by the percent into the current input file, based on byte offsets. The line used is determined by the X as with the %b option.
%PX: Replaced by the percent into the current input file, based on line numbers. The line used is determined by the X as with the %b option.
%s: Same as %B.
%t: Causes any trailing spaces to be removed. Usually used at the end of the string, but may appear anywhere.
%x: Replaced by the name of the next input file in the list.
%K: Replaced by the name of the last non ASCII character set or code set.

If any item is unknown (for example, the file size if input is a pipe), a question mark is printed instead.
The format of the prompt string can be changed depending on certain conditions. A question mark followed by a single character acts like an "IF": depending on the following character, a condition is evaluated. If the condition is true, any characters following the question mark and condition character, up to a period, are included in the prompt. If the condition is false, such characters are not included. A colon appearing between the question mark and the period can be used to establish an "ELSE": any characters between the colon and the period are included in the string if and only if the IF condition is false. Condition characters (which follow a question mark) may be:

?a: True if any characters have been included in the prompt so far.
?bX: True if the byte offset of the specified line is known.
?B: True if the size of current input file is known.
?c: True if the text is horizontally shifted (%c is not zero).
?dX: True if the page number of the specified line is known.
?e: True if at end-of-file.
?f: True if there is an input filename (that is, if input is not a pipe).
?lX: True if the line number of the specified line is known.
?L: True if the line number of the last line in the file is known.
?m: True if there is more than one input file.
?n: True if this is the first prompt in a new input file.
?pX: True if the percent into the current input file, based on byte offsets, of the specified line is known.
?PX: True if the percent into the current input file, based on line numbers, of the specified line is known.
?s: Same as "?B".
?x: True if there is a next input file (that is, if the current input file is not the last one).

Any characters other than the special ones (question mark, colon, period, percent, and backslash) become literally part of the prompt. Any of the special characters may be included in the prompt literally by preceding it with a backslash.
Some examples:
?f%f:Standard input.
This prompt prints the filename, if known; otherwise the string "Standard input".
?f%f .?ltLine %lt:?pt%pt\%:?btByte %bt:-...
This prompt would print the filename, if known. The filename is followed by the line number, if known, otherwise the percent if known, otherwise the byte offset if known. Otherwise, a dash is printed. Notice how each question mark has a matching period, and how the % after the %pt is included literally by escaping it with a backslash.
?n?f%f .?m(file %i of %m) ..?e(END) ?x- Next\: %x..%t
This prints the filename if this is the first prompt in a file, followed by the "file N of N" message if there is more than one input file. Then, if we are at end-of-file, the string "(END)" is printed followed by the name of the next file, if there is one. Finally, any trailing spaces are truncated. This is the default prompt. For reference, here are the defaults for the other two prompts (-m and -M respectively). Each is broken into two lines here for readability only.

?n?f%f .?m(file %i of %m) ..?e(END) ?x- Next\: %x.:
        ?pB%pB\%:byte %bB?s/%s...%t

?f%f .?n?m(file %i of %m) ..?ltlines %lt-%lb?L/%L. :
        byte %bB?s/%s. .?e(END) ?x- Next\: %x.:?pB%pB\%..%t

And here is the default message produced by the = command:

?f%f .?m(file %i of %m) .?ltlines %lt-%lb?L/%L. .
        byte %bB?s/%s. ?e(END) :?pB%pB\%..%t

The prompt expansion features are also used for another purpose: if an environment variable LESSEDIT is defined, it is used as the command to be executed when the v command is invoked. The LESSEDIT string is expanded in the same way as the prompt strings. The default value for LESSEDIT is:

%E ?lm+%lm. %f

Note that this expands to the editor name, followed by a + and the line number, followed by the file name. If your editor does not accept the "+linenumber" syntax, or has other differences in invocation syntax, the LESSEDIT variable can be changed to modify this default.

SECURITY

When the environment variable LESSSECURE is set to 1, less runs in a "secure" mode. This means these features are disabled:

!: the shell command
|: the pipe command
:e: the examine command.
v: the editing command
s -o: log files
-k: use of lesskey files
-t: use of tags files; metacharacters in filenames, such as *; filename completion (TAB, ^L)

Less can also be compiled to be permanently in "secure" mode.

WARNINGS

The = command and prompts (unless changed by -P) report the line numbers of the lines at the top and bottom of the screen, but the byte and percent of the line after the one at the bottom of the screen. If the :e command is used to name more than one file, and one of the named files has been viewed previously, the new files may be entered into the list in an unexpected order.
On certain older terminals (the so-called "magic cookie" terminals), search highlighting will cause an erroneous display. On such terminals, search highlighting is disabled by default to avoid possible problems.
In certain cases, when search highlighting is enabled and a search pattern begins with a ^, more text than the matching string may be highlighted. (This problem does not occur when less is compiled to use the POSIX regular expression package.)
When viewing text containing ANSI color escape sequences using the -R option, searching will not find text containing an embedded escape sequence. Also, search highlighting may change the color of some of the text which follows the highlighted text.
On some systems, setlocale claims that ASCII characters 0 thru 31 are control characters rather than binary characters. This causes less to treat some binary files as ordinary, non-binary files. To workaround this problem, set the environment variable LESSCHARSET to "ascii" (or whatever character set is appropriate).
See http://www.greenwoodsoftware.com/less for the latest list of known bugs in this version of less.

Linux / Unix Command: telnet

NAME

telnet - user interface to the TELNET protocol

SYNOPSIS

telnet [-8EFKLacdfrx ] [-X authtype ] [-b hostalias ] [-e escapechar ] [-k realm ] [-l user ] [-n tracefile ] [host [port ] ]

DESCRIPTION

The telnet command is used to communicate with another host using the TELNET protocol. If telnet is invoked without the host argument, it enters command mode, indicated by its prompt (telnet> ) In this mode, it accepts and executes the commands listed below. If it is invoked with arguments, it performs an open command with those arguments.

The options are as follows:

-8: Specifies an 8-bit data path. This causes an attempt to negotiate the TELNET BINARY option on both input and output.
-E: Stops any character from being recognized as an escape character.
-F: If Kerberos V5 authentication is being used, the -F option allows the local credentials to be forwarded to the remote system, including any credentials that have already been forwarded into the local environment.
-K: Specifies no automatic login to the remote system.
-L: Specifies an 8-bit data path on output. This causes the BINARY option to be negotiated on output.
-X atype: Disables the atype type of authentication.
-a: Attempt automatic login. Currently, this sends the user name via the USER variable of the ENVIRON option if supported by the remote system. The name used is that of the current user as returned by getlogin(2) if it agrees with the current user ID, otherwise it is the name associated with the user ID.
-b hostalias: Uses bind(2) on the local socket to bind it to an aliased address (see ifconfig(8) and the ``alias'' specifier) or to the address of another interface than the one naturally chosen by connect(2). This can be useful when connecting to services which use IP addresses for authentication and reconfiguration of the server is undesirable (or impossible).
-c: Disables the reading of the user's .telnetrc file. (See the toggle skiprc command on this man page.)
-d: Sets the initial value of the debug toggle to TRUE
-e escapechar: Sets the initial telnet escape character to escapechar If escapechar is omitted, then there will be no escape character.
-f: If Kerberos V5 authentication is being used, the -f option allows the local credentials to be forwarded to the remote system.
-k realm: If Kerberos authentication is being used, the -k option requests that telnet obtain tickets for the remote host in realm realm instead of the remote host's realm, as determined by krb_realmofhost3.
-l user: When connecting to the remote system, if the remote system understands the ENVIRON option, then user will be sent to the remote system as the value for the variable USER. This option implies the -a option. This option may also be used with the open command.
-n tracefile: Opens tracefile for recording trace information. See the set tracefile command below.
-r: Specifies a user interface similar to rlogin(1). In this mode, the escape character is set to the tilde (~) character, unless modified by the -e option.
-x: Turns on encryption of the data stream if possible.
host: Indicates the official name, an alias, or the Internet address of a remote host.
port: Indicates a port number (address of an application). If a number is not specified, the default telnet port is used.

When in rlogin mode, a line of the form ~. disconnects from the remote host; ~ is the telnet escape character. Similarly, the line ~^Z suspends the telnet session. The line ~^] escapes to the normal telnet escape prompt.
Once a connection has been opened, telnet will attempt to enable the TELNET LINEMODE option. If this fails, telnet will revert to one of two input modes: either ``character at a time'' or ``old line by line'' depending on what the remote system supports.
When LINEMODE is enabled, character processing is done on the local system, under the control of the remote system. When input editing or character echoing is to be disabled, the remote system will relay that information. The remote system will also relay changes to any special characters that happen on the remote system, so that they can take effect on the local system.
In ``character at a time'' mode, most text typed is immediately sent to the remote host for processing.
In ``old line by line'' mode, all text is echoed locally, and (normally) only completed lines are sent to the remote host. The ``local echo character'' (initially ``^E'') may be used to turn off and on the local echo (this would mostly be used to enter passwords without the password being echoed).
If the LINEMODE option is enabled, or if the localchars toggle is TRUE (the default for ``old line by line''; see below), the user's quit intr and flush characters are trapped locally, and sent as TELNET protocol sequences to the remote side. If LINEMODE has ever been enabled, then the user's susp and eof are also sent as TELNET protocol sequences, and quit is sent as a TELNET ABORT instead of BREAK There are options (see toggle autoflush and toggle autosynch below) which cause this action to flush subsequent output to the terminal (until the remote host acknowledges the TELNET sequence) and flush previous terminal input (in the case of quit and intr )
While connected to a remote host, telnet command mode may be entered by typing the telnet ``escape character'' (initially ``^]''). When in command mode, the normal terminal editing conventions are available. Note that the escape character will return to the command mode of the initial invocation of telnet that has the controlling terminal. Use the send escape command to switch to command mode in subsequent telnet processes on remote hosts.
The following telnet commands are available. Only enough of each command to uniquely identify it need be typed (this is also true for arguments to the mode set toggle unset slc environ and display commands).

auth argument [... ]

The auth command manipulates the information sent through the TELNET AUTHENTICATE option. Valid arguments for the auth command are as follows:

disable type: Disables the specified type of authentication. To obtain a list of available types, use the auth disable ? command.
enable type: Enables the specified type of authentication. To obtain a list of available types, use the auth enable ? command.
status: Lists the current status of the various types of authentication.

close

Close a TELNET session and return to command mode.

display argument [... ]

Displays all, or some, of the set and toggle values (see below).

encrypt argument [... ]

The encrypt command manipulates the information sent through the TELNET ENCRYPT option. Valid arguments for the encrypt command are as follows:

disable type [input|output]: Disables the specified type of encryption. If you omit input and output both input and output are disabled. To obtain a list of available types, use the encrypt disable ? command.
enable type [input|output]: Enables the specified type of encryption. If you omit input and output both input and output are enabled. To obtain a list of available types, use the encrypt enable ? command.
input: This is the same as the encrypt start input command.
-input: This is the same as the encrypt stop input command.
output: This is the same as the encrypt start output command.
-output: This is the same as the encrypt stop output command.
start [input|output]: Attempts to start encryption. If you omit input and output both input and output are enabled. To obtain a list of available types, use the encrypt enable ? command.
status: Lists the current status of encryption.
stop [input|output]: Stops encryption. If you omit input and output encryption is on both input and output.
type type: Sets the default type of encryption to be used with later encrypt start or encrypt stop commands.

environ arguments [... ]

The environ command is used to manipulate the variables that may be sent through the TELNET ENVIRON option. The initial set of variables is taken from the users environment, with only the DISPLAY and PRINTER variables being exported by default. The USER variable is also exported if the -a or -l options are used.
Valid arguments for the environ command are:

define variable value: Define the variable variable to have a value of value Any variables defined by this command are automatically exported. The value may be enclosed in single or double quotes so that tabs and spaces may be included.
undefine variable: Remove variable from the list of environment variables.
export variable: Mark the variable variable to be exported to the remote side.
unexport variable: Mark the variable variable to not be exported unless explicitly asked for by the remote side.
list: List the current set of environment variables. Those marked with a * will be sent automatically, other variables will only be sent if explicitly requested.
?: Prints out help information for the environ command.

logout

Sends the TELNET LOGOUT option to the remote side. This command is similar to a close command; however, if the remote side does not support the LOGOUT option, nothing happens. If, however, the remote side does support the LOGOUT option, this command should cause the remote side to close the TELNET connection. If the remote side also supports the concept of suspending a user's session for later reattachment, the logout argument indicates that you should terminate the session immediately.

mode type

type is one of several options, depending on the state of the TELNET session. The remote host is asked for permission to go into the requested mode. If the remote host is capable of entering that mode, the requested mode will be entered.

character: Disable the TELNET LINEMODE option, or, if the remote side does not understand the LINEMODE option, then enter ``character at a time'' mode.
line: Enable the TELNET LINEMODE option, or, if the remote side does not understand the LINEMODE option, then attempt to enter ``old-line-by-line'' mode.
isig (-isig ): Attempt to enable (disable) the TRAPSIG mode of the LINEMODE option. This requires that the LINEMODE option be enabled.
edit (-edit ): Attempt to enable (disable) the EDIT mode of the LINEMODE option. This requires that the LINEMODE option be enabled.
softtabs (-softtabs ): Attempt to enable (disable) the SOFT_TAB mode of the LINEMODE option. This requires that the LINEMODE option be enabled.
litecho (-litecho ): Attempt to enable (disable) the LIT_ECHO mode of the LINEMODE option. This requires that the LINEMODE option be enabled.
?: Prints out help information for the mode command.

open host [-l user ] [[- ] port ]

Open a connection to the named host. If no port number is specified, telnet will attempt to contact a TELNET server at the default port. The host specification may be either a host name (see hosts(5)) or an Internet address specified in the ``dot notation'' (see inet(3)). The -l option may be used to specify the user name to be passed to the remote system via the ENVIRON option. When connecting to a non-standard port, telnet omits any automatic initiation of TELNET options. When the port number is preceded by a minus sign, the initial option negotiation is done. After establishing a connection, the file .telnetrc in the user's home directory is opened. Lines beginning with a ``#'' are comment lines. Blank lines are ignored. Lines that begin without whitespace are the start of a machine entry. The first thing on the line is the name of the machine that is being connected to. The rest of the line, and successive lines that begin with whitespace are assumed to be telnet commands and are processed as if they had been typed in manually to the telnet command prompt.

quit

Close any open TELNET session and exit telnet An end-of-file (in command mode) will also close a session and exit.

send arguments

Sends one or more special character sequences to the remote host. The following are the arguments which may be specified (more than one argument may be specified at a time):

abort: Sends the TELNET ABORT (Abort processes) sequence.
ao: Sends the TELNET AO (Abort Output) sequence, which should cause the remote system to flush all output from the remote system to the user's terminal.
ayt: Sends the TELNET AYT (Are You There) sequence, to which the remote system may or may not choose to respond.
brk: Sends the TELNET BRK (Break) sequence, which may have significance to the remote system.
ec: Sends the TELNET EC (Erase Character) sequence, which should cause the remote system to erase the last character entered.
el: Sends the TELNET EL (Erase Line) sequence, which should cause the remote system to erase the line currently being entered.
eof: Sends the TELNET EOF (End Of File) sequence.
eor: Sends the TELNET EOR (End of Record) sequence.
escape: Sends the current telnet escape character (initially ``^]'').
ga: Sends the TELNET GA (Go Ahead) sequence, which likely has no significance to the remote system.
getstatus: If the remote side supports the TELNET STATUS command, getstatus will send the subnegotiation to request that the server send its current option status.
ip: Sends the TELNET IP (Interrupt Process) sequence, which should cause the remote system to abort the currently running process.
nop: Sends the TELNET NOP (No OPeration) sequence.
susp: Sends the TELNET SUSP (SUSPend process) sequence.
synch: Sends the TELNET SYNCH sequence. This sequence causes the remote system to discard all previously typed (but not yet read) input. This sequence is sent as TCP urgent data (and may not work if the remote system is a BSD 4.2 system -- if it doesn't work, a lower case ``r'' may be echoed on the terminal).
do cmd: Sends the TELNET DO cmd sequence. cmd can be either a decimal number between 0 and 255, or a symbolic name for a specific TELNET command. cmd can also be either help or ? to print out help information, including a list of known symbolic names.
dont cmd: Sends the TELNET DONT cmd sequence. cmd can be either a decimal number between 0 and 255, or a symbolic name for a specific TELNET command. cmd can also be either help or ? to print out help information, including a list of known symbolic names.
will cmd: Sends the TELNET WILL cmd sequence. cmd can be either a decimal number between 0 and 255, or a symbolic name for a specific TELNET command. cmd can also be either help or ? to print out help information, including a list of known symbolic names.
wont cmd: Sends the TELNET WONT cmd sequence. cmd can be either a decimal number between 0 and 255, or a symbolic name for a specific TELNET command. cmd can also be either help or ? to print out help information, including a list of known symbolic names.
?: Prints out help information for the send command.

set argument value

unset argument value

The set command will set any one of a number of telnet variables to a specific value or to TRUE The special value off turns off the function associated with the variable; this is equivalent to using the unset command. The unset command will disable or set to FALSE any of the specified functions. The values of variables may be interrogated with the display command. The variables which may be set or unset, but not toggled, are listed here. In addition, any of the variables for the toggle command may be explicitly set or unset using the set and unset commands.

ayt: If TELNET is in localchars mode, or LINEMODE is enabled, and the status character is typed, a TELNET AYT sequence (see send ayt preceding) is sent to the remote host. The initial value for the "Are You There" character is the terminal's status character.
echo: This is the value (initially ``^E'') which, when in ``line by line'' mode, toggles between doing local echoing of entered characters (for normal processing), and suppressing echoing of entered characters (for entering, say, a password).
eof: If telnet is operating in LINEMODE or ``old line by line'' mode, entering this character as the first character on a line will cause this character to be sent to the remote system. The initial value of the eof character is taken to be the terminal's eof character.
erase: If telnet is in localchars mode (see toggle localchars below), and if telnet is operating in ``character at a time'' mode, then when this character is typed, a TELNET EC sequence (see send ec above) is sent to the remote system. The initial value for the erase character is taken to be the terminal's erase character.
escape: This is the telnet escape character (initially ``^['') which causes entry into telnet command mode (when connected to a remote system).
flushoutput: If telnet is in localchars mode (see toggle localchars below) and the flushoutput character is typed, a TELNET AO sequence (see send ao above) is sent to the remote host. The initial value for the flush character is taken to be the terminal's flush character.
forw1
forw2: If TELNET is operating in LINEMODE these are the characters that, when typed, cause partial lines to be forwarded to the remote system. The initial value for the forwarding characters are taken from the terminal's eol and eol2 characters.
interrupt: If telnet is in localchars mode (see toggle localchars below) and the interrupt character is typed, a TELNET IP sequence (see send ip above) is sent to the remote host. The initial value for the interrupt character is taken to be the terminal's intr character.
kill: If telnet is in localchars mode (see toggle localchars below), and if telnet is operating in ``character at a time'' mode, then when this character is typed, a TELNET EL sequence (see send el above) is sent to the remote system. The initial value for the kill character is taken to be the terminal's kill character.
lnext: If telnet is operating in LINEMODE or ``old line by line'' mode, then this character is taken to be the terminal's lnext character. The initial value for the lnext character is taken to be the terminal's lnext character.
quit: If telnet is in localchars mode (see toggle localchars below) and the quit character is typed, a TELNET BRK sequence (see send brk above) is sent to the remote host. The initial value for the quit character is taken to be the terminal's quit character.
reprint: If telnet is operating in LINEMODE or old line by line'' mode, then this character is taken to be the terminal's reprint character. The initial value for the reprint character is taken to be the terminal's reprint character.
rlogin: This is the rlogin escape character. If set, the normal TELNET escape character is ignored unless it is preceded by this character at the beginning of a line. This character, at the beginning of a line, followed by a "." closes the connection; when followed by a ^Z it suspends the telnet command. The initial state is to disable the rlogin escape character.
start: If the TELNET TOGGLE-FLOW-CONTROL option has been enabled, then this character is taken to be the terminal's start character. The initial value for the start character is taken to be the terminal's start character.
stop: If the TELNET TOGGLE-FLOW-CONTROL option has been enabled, then this character is taken to be the terminal's stop character. The initial value for the stop character is taken to be the terminal's stop character.
susp: If telnet is in localchars mode, or LINEMODE is enabled, and the suspend character is typed, a TELNET SUSP sequence (see send susp above) is sent to the remote host. The initial value for the suspend character is taken to be the terminal's suspend character.
tracefile: This is the file to which the output, caused by netdata or option tracing being TRUE will be written. If it is set to ``- '' then tracing information will be written to standard output (the default).
worderase: If telnet is operating in LINEMODE or ``old line by line'' mode, then this character is taken to be the terminal's worderase character. The initial value for the worderase character is taken to be the terminal's worderase character.
?: Displays the legal set (unset ) commands.

skey sequence challenge

The skey command computes a response to the S/Key challenge. See skey(1) for more information on the S/Key system.

slc state

The slc command (Set Local Characters) is used to set or change the state of the special characters when the TELNET LINEMODE option has been enabled. Special characters are characters that get mapped to TELNET commands sequences (like ip or quit or line editing characters (like erase and kill ) By default, the local special characters are exported.

check: Verify the current settings for the current special characters. The remote side is requested to send all the current special character settings, and if there are any discrepancies with the local side, the local side will switch to the remote value.
export: Switch to the local defaults for the special characters. The local default characters are those of the local terminal at the time when telnet was started.
import: Switch to the remote defaults for the special characters. The remote default characters are those of the remote system at the time when the TELNET connection was established.
?: Prints out help information for the slc command.

status

Show the current status of telnet This includes the peer one is connected to, as well as the current mode.

toggle arguments [... ]

Toggle (between TRUE and FALSE various flags that control how telnet responds to events. These flags may be set explicitly to TRUE or FALSE using the set and unset commands listed above. More than one argument may be specified. The state of these flags may be interrogated with the display command. Valid arguments are:

authdebug: Turns on debugging information for the authentication code.
autoflush: If autoflush and localchars are both TRUE then when the ao or quit characters are recognized (and transformed into TELNET sequences; see set above for details), telnet refuses to display any data on the user's terminal until the remote system acknowledges (via a TELNET TIMING MARK option) that it has processed those TELNET sequences. The initial value for this toggle is TRUE if the terminal user had not done an "stty noflsh", otherwise FALSE (see stty(1)).
autodecrypt: When the TELNET ENCRYPT option is negotiated, by default the actual encryption (decryption) of the data stream does not start automatically. The autoencrypt (autodecrypt ) command states that encryption of the output (input) stream should be enabled as soon as possible.
autologin: If the remote side supports the TELNET AUTHENTICATION option TELNET attempts to use it to perform automatic authentication. If the AUTHENTICATION option is not supported, the user's login name are propagated through the TELNET ENVIRON option. This command is the same as specifying a option on the open command.
autosynch: If autosynch and localchars are both TRUE then when either the intr or quit character is typed (see set above for descriptions of the intr and quit characters), the resulting TELNET sequence sent is followed by the TELNET SYNCH sequence. This procedure should cause the remote system to begin throwing away all previously typed input until both of the TELNET sequences have been read and acted upon. The initial value of this toggle is FALSE
binary: Enable or disable the TELNET BINARY option on both input and output.
inbinary: Enable or disable the TELNET BINARY option on input.
outbinary: Enable or disable the TELNET BINARY option on output.
crlf: If this is TRUE then carriage returns will be sent as If this is FALSE then carriage returns will be send as The initial value for this toggle is FALSE
crmod: Toggle carriage return mode. When this mode is enabled, most carriage return characters received from the remote host will be mapped into a carriage return followed by a line feed. This mode does not affect those characters typed by the user, only those received from the remote host. This mode is not very useful unless the remote host only sends carriage return, but never line feeds. The initial value for this toggle is FALSE
debug: Toggles socket level debugging (useful only to the superuser). The initial value for this toggle is FALSE
encdebug: Turns on debugging information for the encryption code.
localchars: If this is TRUE then the flush interrupt quit erase and kill characters (see set above) are recognized locally, and transformed into (hopefully) appropriate TELNET control sequences (respectively ao ip brk ec and el see send above). The initial value for this toggle is TRUE in ``old line by line'' mode, and FALSE in ``character at a time'' mode. When the LINEMODE option is enabled, the value of localchars is ignored, and assumed to always be TRUE If LINEMODE has ever been enabled, then quit is sent as abort and eof and suspend are sent as eof and susp (see send above).
netdata: Toggles the display of all network data (in hexadecimal format). The initial value for this toggle is FALSE
options: Toggles the display of some internal telnet protocol processing (having to do with TELNET options). The initial value for this toggle is FALSE
prettydump: When the netdata toggle is enabled, if prettydump is enabled the output from the netdata command will be formatted in a more user readable format. Spaces are put between each character in the output, and the beginning of any TELNET escape sequence is preceded by a '*' to aid in locating them.
skiprc: When the skiprc toggle is TRUE TELNET skips the reading of the .telnetrc file in the user's home directory when connections are opened. The initial value for this toggle is FALSE
termdata: Toggles the display of all terminal data (in hexadecimal format). The initial value for this toggle is FALSE
verbose_encrypt: When the verbose_encrypt toggle is TRUE telnet prints out a message each time encryption is enabled or disabled. The initial value for this toggle is FALSE
?: Displays the legal toggle commands.

z

Suspend telnet This command only works when the user is using the csh(1).

! [command ]

Execute a single command in a subshell on the local system. If command is omitted, then an interactive subshell is invoked.

? [command ]

Get help. With no arguments, telnet prints a help summary. If a command is specified, telnet will print the help information for just that command.

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Linux / Unix Command: tar

NAME

SYNOPSIS

DESCRIPTION

FUNCTION LETTERS

OTHER OPTIONS

Linux / Unix Command: less

NAME

EXAMPLES

SYNOPSIS

DESCRIPTION

COMMANDS

OPTIONS

LINE EDITING

KEY BINDINGS

INPUT PREPROCESSOR

NATIONAL CHARACTER SETS

PROMPTS

SECURITY

SEE ALSO

WARNINGS

Linux / Unix Command: telnet

NAME

SYNOPSIS

DESCRIPTION