LESS(1) manual page
Table of Contents
less - opposite of more
less -?
less --help
less -V
less --version
less [-[+]aABcCdeEfFgGiIJKLmMnNqQrRsSuUVwWX~]
[-b space] [-h lines] [-j line] [-k keyfile]
[-{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.)
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.
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.
- ENTER or 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.)
- ESC-F
- Like F, but as soon as a line is found which matches the
last search pattern, the terminal bell is rung and forward scrolling stops.
- 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, and may contain a decimal point.
- P
- Go to the line containing byte offset
N in the file.
- {
- 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 the regular
expression library supplied by your system. The search starts at the first
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.)
- &pattern
- Display
only lines which match the pattern; lines which do not match the pattern
are not displayed. If pattern is empty (if you type & immediately followed
by ENTER), any filtering is turned off, and all lines are displayed. While
filtering is in effect, an ampersand is displayed at the beginning of the
prompt, as a reminder that some lines in the file may be hidden.
Certain
characters are special as in the / command:
- ^N or !
- Display only lines which
do NOT match the pattern.
- ^R
- Don’t interpret regular expression metacharacters;
that is, do a simple textual comparison.
- :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.
- -
- 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 ENTER or 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 ENTER or 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.
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". 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 environment variable. If an option
appears in the LESS variable, it can be reset to its default value on the
command line by beginning the command line option with "-+".
Some options
like -k or -D require a string to follow the option letter. The string for
that option is considered to end when a dollar sign ($) is found. For example,
you can set two -D options on MS-DOS like this:
LESS="Dn9.1$Ds4.1"
If the --use-backslash
option appears earlier in the options, then a dollar sign or backslash
may be included literally in an option string by preceding it with a backslash.
If the --use-backslash option is not in effect, then backslashes are not treated
specially, and there is no way to include a dollar sign in the option
string.
- -? 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
- By default, forward searches start at the top
of the displayed screen and backwards searches start at the bottom of the
displayed screen (except for repeated searches invoked by the n or N commands,
which start after or before the "target" line respectively; see the -j option
for more about the target line). The -a option causes forward searches to
instead start at the bottom of the screen and backward searches to start
at the top of the screen, thus skipping all lines displayed on the screen.
- -A or --SEARCH-SKIP-SCREEN
- Causes all forward searches (not just non-repeated
searches) to start just after the target line, and all backward searches
to start just before the target line. Thus, forward searches will skip
part of the displayed screen (from the first line up to and including the
target line). Similarly backwards searches will skip the displayed screen
from the last line up to and including the target line. This was the default
behavior in less versions prior to 441.
- -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 can be 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 piped data 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
- Same as -c, for compatibility with
older versions of less.
- -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.M, where M is the normal background color.
- -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. Note that some operating systems will not allow directories
to be read, even if -f is set.
- -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. The target line is the line
specified by any command to search for a pattern, jump to a line number,
jump to a file percentage or jump to a tag. The screen line may be 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. Alternately, the screen line may be specified as a fraction
of the height of the screen, starting with a decimal point: .5 is in the
middle of the screen, .3 is three tenths down from the first line, and so
on. If the line is specified as a fraction, the actual line number is recalculated
if the terminal window is resized, so that the target line remains at the
specified fraction of the screen height. If any form of the -j option is
used, forward searches begin at the line immediately after the target
line, and backward searches begin at the target line, unless changed by
-a or -A. For example, if "-j4" is used, the target line is the fourth line
on the screen, so forward 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.
- -K or --quit-on-intr
- Causes
less to exit immediately (with status 2) when an interrupt character (usually
^C) is typed. Normally, an interrupt character causes less to stop whatever
it is doing and return to its command prompt. Note that use of this option
makes it impossible to return to the command prompt from the "F" command.
- -L or --no-lessopen
- Ignore the LESSOPEN environment variable (see the INPUT
PREPROCESSOR section below). This option can be set from within less, but
it will apply only to files opened subsequently, not to the file which
is currently open.
- -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 environment variable, rather than being typed in with each
less command. Such an option must either be the last option in the LESS
variable, 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 only ANSI "color" escape sequences are
output in "raw" form. Unlike -r, the screen appearance is maintained correctly
in most cases. ANSI "color" escape sequences are sequences of the form:
ESC [ ... m
where the "..." is zero or more color specification characters For the purpose
of keeping track of screen appearance, 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. And you can make less think that characters other than
the standard ones may appear between the ESC and the m by setting the
environment variable LESSANSIMIDCHARS to the list of characters which can
appear.
- -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 (truncated)
rather than wrapped. That is, the portion of a long line that does not fit
in the screen width is not shown. The default is to wrap 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.
- -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 some versions of 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.
- -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. Alternately, the number may be specified as a
fraction of the width of the screen, starting with a decimal point: .5 is
half of the screen width, .3 is three tenths of the screen width, and so
on. If the number is specified as a fraction, the actual number of scroll
positions is recalculated if the terminal window is resized, so that the
actual scroll remains at the specified fraction of the screen width.
- --follow-name
- Normally,
if the input file is renamed while an F command is executing, less will
continue to display the contents of the original file despite its name
change. If --follow-name is specified, during an F command less will periodically
attempt to reopen the file by name. If the reopen succeeds and the file
is a different file from the original (which means that a new file has
been created with the same name as the original (now renamed) file), less
will display the contents of that new file.
- --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.
- --use-backslash
- This option changes the interpretations
of options which follow this one. After the --use-backslash option, any backslash
in an option string is removed and the following character is taken literally.
This allows a dollar sign to be included in option strings.
- --
- 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.
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. (Note that the forms
beginning with ESC do not work in some MS-DOS and Windows systems because
ESC is the line erase character.) 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. If you first enter some text and then press UPARROW, it will
retrieve the previous command which begins with that text.
- DOWNARROW [ ESC-j
]
- Retrieve the next command line. If you first enter some text and then press
DOWNARROW, it will retrieve the next command which begins with that text.
- 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.
- ^G
- Delete the entire command line and return to the
main prompt.
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.
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 - $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
*) exit 1
;;
esac
exit $?
To use this script, put it where it can be executed and set LESSOPEN="|lesspipe.sh
%s".
Note that a preprocessor cannot output an empty file, since that is
interpreted as meaning there is no replacement, and the original file
is used. To avoid this, if LESSOPEN starts with two vertical bars, the exit
status of the script becomes meaningful. If the exit status is zero, the
output is considered to be replacement text, even if it empty. If the exit
status is nonzero, any output is ignored and the original file is used.
For compatibility with previous versions of less, if LESSOPEN starts with
only one vertical bar, the exit status of the preprocessor is ignored.
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 "-".
For compatibility with previous versions of less, the input preprocessor
or pipe is not used if less is viewing standard input. However, if the
first character of LESSOPEN is a dash (-), the input preprocessor is used
on standard input as well as other files. In this case, the dash is not
considered to be part of the preprocessor command. If standard input is
being viewed, the input preprocessor is passed a file name consisting of
a single dash. Similarly, if the first two characters of LESSOPEN are vertical
bar and dash (|-) or two vertical bars and a dash (||-), the input pipe is
used on standard input as well as other files. Again, in this case the dash
is not considered to be part of the input pipe command.
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 LESSCHARSET environment variable may be used to select a
character set. Possible values for LESSCHARSET 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. UTF-8 is special in that it supports multi-byte characters in the input
file. It is the only character set that supports multi-byte characters.
- windows
- Selects
a character set appropriate for Microsoft Windows (cp 1251).
In rare 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 any of the strings
"UTF-8", "UTF8", "utf-8" or "utf8" is found in the LC_ALL, LC_CTYPE 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<%02X>". Warning: the result of expanding
the character via LESSBINFMT must be less than 31 characters.
When the character
set is utf-8, the LESSUTFBINFMT environment variable acts similarly to LESSBINFMT
but it applies to Unicode code points that were successfully decoded but
are unsuitable for display (e.g., unassigned code points). Its default value
is "<U+%04lX>". Note that LESSUTFBINFMT and LESSBINFMT share their display
attribute setting ("*x") so specifying one will affect both; LESSUTFBINFMT
is read after LESSBINFMT so its setting, if any, will have priority. Problematic
octets in a UTF-8 file (octets of a truncated sequence, octets of a complete
but non-shortest form sequence, illegal octets, and stray trailing octets)
are displayed individually using LESSBINFMT so as to facilitate diagnostic
of how the UTF-8 file is ill-formed.
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.
- %F
- Replaced by the
last component of 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.
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.
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.
If the environment variable LESS_IS_MORE is set to 1, or if the
program is invoked via a file link named "more", less behaves (mostly)
in conformance with the POSIX "more" command specification. In this mode,
less behaves differently in these ways:
The -e option works differently.
If the -e option is not set, less behaves as if the -E option were set. If
the -e option is set, less behaves as if the -e and -F options were set.
The
-m option works differently. If the -m option is not set, the medium prompt
is used, and it is prefixed with the string "--More--". If the -m option is set,
the short prompt is used.
The -n option acts like the -z option. The normal
behavior of the -n option is unavailable in this mode.
The parameter to the
-p option is taken to be a less command rather than a search pattern.
The
LESS environment variable is ignored, and the MORE environment variable
is used in its place.
Environment variables may be
specified either in the system environment as usual, or in a lesskey (1)
file. If environment variables are defined in more than one place, variables
defined in a local lesskey file take precedence over variables defined
in the system environment, which take precedence over variables defined
in the system-wide lesskey file.
- COLUMNS
- Sets the number of columns on the
screen. Takes precedence over the number of columns specified by the TERM
variable. (But if you have a windowing system which supports TIOCGWINSZ
or WIOCGETD, the window system’s idea of the screen size takes precedence
over the LINES and COLUMNS environment variables.)
- EDITOR
- The name of the
editor (used for the v command).
- HOME
- Name of the user’s home directory (used
to find a lesskey file on Unix and OS/2 systems).
- HOMEDRIVE, HOMEPATH
- Concatenation
of the HOMEDRIVE and HOMEPATH environment variables is the name of the
user’s home directory if the HOME variable is not set (only in the Windows
version).
- INIT
- Name of the user’s init directory (used to find a lesskey file
on OS/2 systems).
- LANG
- Language for determining the character set.
- LC_CTYPE
- Language
for determining the character set.
- LESS
- Options which are passed to less
automatically.
- LESSANSIENDCHARS
- Characters which may end an ANSI color escape
sequence (default "m").
- LESSANSIMIDCHARS
- Characters which may appear between
the ESC character and the end character in an ANSI color escape sequence
(default "0123456789;[?!"’#%()*+ ".
- LESSBINFMT
- Format for displaying non-printable,
non-control characters.
- LESSCHARDEF
- Defines a character set.
- LESSCHARSET
- Selects
a predefined character set.
- LESSCLOSE
- Command line to invoke the (optional)
input-postprocessor.
- LESSECHO
- Name of the lessecho program (default "lessecho").
The lessecho program is needed to expand metacharacters, such as * and
?, in filenames on Unix systems.
- LESSEDIT
- Editor prototype string (used for
the v command). See discussion under PROMPTS.
- LESSGLOBALTAGS
- Name of the command
used by the -t option to find global tags. Normally should be set to "global"
if your system has the global (1)
command. If not set, global tags are
not used.
- LESSHISTFILE
- Name of the history file used to remember search commands
and shell commands between invocations of less. If set to "-" or "/dev/null",
a history file is not used. The default is "$HOME/.lesshst" on Unix systems,
"$HOME/_lesshst" on DOS and Windows systems, or "$HOME/lesshst.ini" or "$INIT/lesshst.ini"
on OS/2 systems.
- LESSHISTSIZE
- The maximum number of commands to save in
the history file. The default is 100.
- LESSKEY
- Name of the default lesskey(1)
file.
- LESSKEY_SYSTEM
- Name of the default system-wide lesskey(1)
file.
- LESSMETACHARS
- List
of characters which are considered "metacharacters" by the shell.
- LESSMETAESCAPE
- Prefix
which less will add before each metacharacter in a command sent to the
shell. If LESSMETAESCAPE is an empty string, commands containing metacharacters
will not be passed to the shell.
- LESSOPEN
- Command line to invoke the (optional)
input-preprocessor.
- LESSSECURE
- Runs less in "secure" mode. See discussion under
SECURITY.
- LESSSEPARATOR
- String to be appended to a directory name in filename
completion.
- LESSUTFBINFMT
- Format for displaying non-printable Unicode code
points.
- LESS_IS_MORE
- Emulate the more (1)
command.
- LINES
- Sets the number of
lines on the screen. Takes precedence over the number of lines specified
by the TERM variable. (But if you have a windowing system which supports
TIOCGWINSZ or WIOCGETD, the window system’s idea of the screen size takes
precedence over the LINES and COLUMNS environment variables.)
- MORE
- Options
which are passed to less automatically when running in more compatible
mode.
- PATH
- User’s search path (used to find a lesskey file on MS-DOS and OS/2
systems).
- SHELL
- The shell used to execute the ! command, as well as to expand
filenames.
- TERM
- The type of terminal on which less is being run.
- VISUAL
- The
name of the editor (used for the v command).
lesskey(1)
Copyright
(C) 1984-2012 Mark Nudelman
less is part of the GNU project and is free
software. You can redistribute it and/or modify it under the terms of either
(1)
the GNU General Public License as published by the Free Software Foundation;
or (2)
the Less License. See the file README in the less distribution for
more details regarding redistribution. You should have received a copy of
the GNU General Public License along with the source for less; see the
file COPYING. If not, write to the Free Software Foundation, 59 Temple Place,
Suite 330, Boston, MA 02111-1307, USA. You should also have received a copy
of the Less License; see the file LICENSE.
less is distributed in the hope
that it will be useful, but WITHOUT ANY WARRANTY; without even the implied
warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
GNU General Public License for more details.
Mark Nudelman
Send bug reports or comments to <bug-less@gnu.org>
See http://www.greenwoodsoftware.com/less/bugs.html
for the latest list of
known bugs in less.
For more information, see the less homepage at
http://www.greenwoodsoftware.com/less.
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