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
64 KB 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
64 KB (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
Changes the color of different parts of the displayed
text. x is a single character which selects the type of
text whose color is being set:
B Binary characters.
C Control characters.
E Errors and informational messages.
M Mark letters in the status column.
N Line numbers enabled via the -N option.
P Prompts.
R The rscroll character.
S Search results.
W The highlight enabled via the -w option.
d Bold text.
k Blinking text.
s Standout text.
u Underlined text.
The uppercase letters can be used only when the --use-
color option is enabled. When text color is specified by
both an uppercase letter and a lowercase letter, the
uppercase letter takes precedence. For example, error
messages are normally displayed as standout text. So if
both "s" and "E" are given a color, the "E" color applies
to error messages, and the "s" color applies to other
standout text. The "d" and "u" letters refer to bold and
underline text formed by overstriking with backspaces (see
the -u option), not to text using ANSI escape sequences
with the -R option.
A lowercase letter may be followed by a + to indicate that
both the normal format change and the specified color
should both be used. For example, -Dug displays
underlined text as green without underlining; the green
color has replaced the usual underline formatting. But
-Du+g displays underlined text as both green and in
underlined format.
color is either a 4-bit color string or an 8-bit color
string:
A 4-bit color string is zero, one or two characters, where
the first character specifies the foreground color and the
second specifies the background color as follows:
b Blue
c Cyan
g Green
k Black
m Magenta
r Red
w White
y Yellow
The corresponding upper-case letter denotes a brighter
shade of the color. For example, -DNGk displays line
numbers as bright green text on a black background, and
-DEbR displays error messages as blue text on a bright red
background. If either character is a "-" or is omitted,
the corresponding color is set to that of normal text.
An 8-bit color string is one or two decimal integers
separated by a dot, where the first integer specifies the
foreground color and the second specifies the background
color. Each integer is a value between 0 and 255
inclusive which selects a "CSI 38;5" color value (see
https://en.wikipedia.org/wiki/ANSI_escape_code#SGR_parameters)
If either integer is a "-" or is omitted, the
corresponding color is set to that of normal text. On MS-
DOS versions of less, 8-bit color is not supported;
instead, decimal values are interpreted as 4-bit
CHAR_INFO.Attributes values (see
https://docs.microsoft.com/en-us/windows/console/char-info-str).
-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, repeated forward
searches (invoked with "n" or "N") begin at the line
immediately after the target line, and repeated 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. However nonrepeated
searches (invoked with "/" or "?") always begin at the
start or end of the current screen respectively.
-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, and any lines that are marked (via the m or M
command).
-kfilename or --lesskey-file=filename
Causes less to open and interpret the named file as a
lesskey(1) binary 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.
--lesskey-src=filename
Causes less to open and interpret the named file as a
lesskey(1) source file. If the LESSKEYIN or
LESSKEYIN_SYSTEM environment variable is set, or if a
lesskey source file is found in a standard place (see KEY
BINDINGS), it is also used as a lesskey source file.
Prior to version 582, the lesskey program needed to be run
to convert a lesskey source file to a lesskey binary file
for less to use. Newer versions of less read the lesskey
source file directly and ignore the binary file if the
source file exists.
-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. If the terminal has a "visual bell", it is
used in all cases where the terminal bell would have been
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.
USE OF THE -r OPTION IS NOT RECOMMENDED.
-R or --RAW-CONTROL-CHARS
Like -r, but only ANSI "color" escape sequences and OSC 8
hyperlink sequences are output in "raw" form. Unlike -r,
the screen appearance is maintained correctly, provided
that there are no escape sequences in the file other than
these types of escape sequences. Color escape sequences
are only supported when the color is changed within one
line, not across lines. In other words, the beginning of
each line is assumed to be normal (non-colored),
regardless of any escape sequences in previous lines. For
the purpose of keeping track of screen appearance, these
escape sequences are assumed to not move the cursor.
OSC 8 hyperlinks are sequences of the form:
ESC ] 8 ; ... \7
The terminating sequence may be either a BEL character
(\7) or the two-character sequence "ESC \".
ANSI color escape sequences are sequences of the form:
ESC [ ... m
where the "..." is zero or more color specification
characters. 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
displayed until you press RIGHT-ARROW. 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, carriage returns and "formatting
characters" (as defined by Unicode) 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. Unicode formatting
characters, such as the Byte Order Mark, are sent to the
terminal. 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.
-zn or --window=n or -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.
--file-size
If --file-size is specified, less will determine the size
of the file immediately after opening the file. Normally
this is not done, because it can be slow if the input file
is large.
--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.
--incsearch
Subsequent search commands will be "incremental"; that is,
less will advance to the next line containing the search
pattern as each character of the pattern is typed in.
--line-num-width
Sets the minimum width of the line number field when the
-N option is in effect. The default is 7 characters.
--mouse
Enables mouse input: scrolling the mouse wheel down moves
forward in the file, scrolling the mouse wheel up moves
backwards in the file, and clicking the mouse sets the "#"
mark to the line where the mouse is clicked. The number
of lines to scroll when the wheel is moved can be set by
the --wheel-lines option. Mouse input works only on
terminals which support X11 mouse reporting, and on the
Windows version of less.
--MOUSE
Like --mouse, except the direction scrolled on mouse wheel
movement is reversed.
--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.
--no-histdups
This option changes the behavior so that if a search
string or file name is typed in, and the same string is
already in the history list, the existing copy is removed
from the history list before the new one is added. Thus,
a given string will appear only once in the history list.
Normally, a string may appear multiple times.
--rscroll
This option changes the character used to mark truncated
lines. It may begin with a two-character attribute
indicator like LESSBINFMT does. If there is no attribute
indicator, standout is used. If set to "-", truncated
lines are not marked.
--save-marks
Save marks in the history file, so marks are retained
across different invocations of less.
--status-col-width
Sets the width of the status column when the -J option is
in effect. The default is 2 characters.
--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.
--use-color
Enables the colored text in various places. The -D option
can be used to change the colors. Colored text works only
if the terminal supports ANSI color escape sequences (as
defined in ECMA-48 SGR; see
https://www.ecma-international.org/publications-and-standards/standards/ecma-48).
--wheel-lines=n
Set the number of lines to scroll when the mouse wheel is
scrolled and the --mouse or --MOUSE option is in effect.
The default is 1 line.
-- 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.
