LESS

LESS(1) General Commands Manual LESS(1)

NAME

less – opposite of more

SYNOPSIS

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.)

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.

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.

😡 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.

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”. 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.

-“cc 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.

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. (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.

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 –
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.

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 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.

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.

%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.

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.

COMPATIBILITY WITH MORE

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

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).

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