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LESS(1)                    General Commands Manual                   LESS(1)

NAME         top

       less - opposite of more

SYNOPSIS         top

       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         top

       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         top

       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.

       J      Like j, but continues to scroll beyond the end of the file.

       K or Y Like k, but continues to scroll beyond the beginning of the
              file.

       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.

       ESC-} or ^RIGHTARROW
              Scroll horizontally right to show the end of the longest
              displayed line.

       ESC-{ or ^LEFTARROW
              Scroll horizontally left back to the first column.

       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.)

       ESC-G  Same as G, except if no number N is specified and the input is
              standard input, goes to the last line which is currently
              buffered.

       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 last line displayed (but
              see the -a and -j options, which change this).

              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.

OPTIONS         top

       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 K 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 K (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.  x
              may also be a to toggle strict ANSI sequence rendering (SGR
              mode).

       -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.
              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         top

       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         top

       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         top

       You may define an "input preprocessor" for less.  Before less opens a
       file, it first gives your input preprocessor a chance to modify the
       way the contents of the file are displayed.  An input preprocessor is
       simply an executable program (or shell script), which writes the
       contents of the file to a different file, called the replacement
       file.  The contents of the replacement file are then displayed in
       place of the contents of the original file.  However, it will appear
       to the user as if the original file is opened; that is, less will
       display the original filename as the name of the current file.

       An input preprocessor receives one command line argument, the
       original filename, as entered by the user.  It should create the
       replacement file, and when finished, print the name of the
       replacement file to its standard output.  If the input preprocessor
       does not output a replacement filename, less uses the original file,
       as normal.  The input preprocessor is not called when viewing
       standard input.  To set up an input preprocessor, set the LESSOPEN
       environment variable to a command line which will invoke your input
       preprocessor.  This command line should include one occurrence of the
       string "%s", which will be replaced by the filename when the input
       preprocessor command is invoked.

       When less closes a file opened in such a way, it will call another
       program, called the input postprocessor, which may perform any
       desired clean-up action (such as deleting the replacement file
       created by LESSOPEN).  This program receives two command line
       arguments, the original filename as entered by the user, and the name
       of the replacement file.  To set up an input postprocessor, set the
       LESSCLOSE environment variable to a command line which will invoke
       your input postprocessor.  It may include two occurrences of the
       string "%s"; the first is replaced with the original name of the file
       and the second with the name of the replacement file, which was
       output by LESSOPEN.

       For example, on many Unix systems, these two scripts will allow you
       to keep files in compressed format, but still let less view them
       directly:

       lessopen.sh:
            #! /bin/sh
            case "$1" in
            *.Z) uncompress -c $1  >/tmp/less.$$  2>/dev/null
                 if [ -s /tmp/less.$$ ]; then
                      echo /tmp/less.$$
                 else
                      rm -f /tmp/less.$$
                 fi
                 ;;
            esac

       lessclose.sh:
            #! /bin/sh
            rm $2

       To use these scripts, put them both where they can be executed and
       set LESSOPEN="lessopen.sh %s", and LESSCLOSE="lessclose.sh %s %s".
       More complex LESSOPEN and LESSCLOSE scripts may be written to accept
       other types of compressed files, and so on.

       It is also possible to set up an input preprocessor to pipe the file
       data directly to less, rather than putting the data into a
       replacement file.  This avoids the need to decompress the entire file
       before starting to view it.  An input preprocessor that works this
       way is called an input pipe.  An input pipe, instead of writing the
       name of a replacement file on its standard output, writes the entire
       contents of the replacement file on its standard output.  If the
       input pipe does not write any characters on its standard output, then
       there is no replacement file and less uses the original file, as
       normal.  To use an input pipe, make the first character in the
       LESSOPEN environment variable a vertical bar (|) to signify that the
       input preprocessor is an input pipe.

       For example, on many Unix systems, this script will work like the
       previous example scripts:

       lesspipe.sh:
            #! /bin/sh
            case "$1" in
            *.Z) uncompress -c $1  2>/dev/null
            *)   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         top

       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         top

       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.

       %T     Normally expands to the word "file".  However if viewing files
              via a tags list using the -t option, it expands to the word
              "tag".

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

       ?f%f .?n?m(%T %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(%T %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         top

       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         top

       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 option 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         top

       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).

SEE ALSO         top

       lesskey(1)

COPYRIGHT         top

       Copyright (C) 1984-2016  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.

AUTHOR         top

       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.

COLOPHON         top

       This page is part of the less (A file pager) project.  Information
       about the project can be found at 
       ⟨http://www.greenwoodsoftware.com/less/⟩.  If you have a bug report
       for this manual page, see 
       ⟨http://www.greenwoodsoftware.com/less/faq.html#bugs⟩.  This page was
       obtained from the tarball less-487.tar.gz fetched from 
       ⟨http://www.greenwoodsoftware.com/less/download.html⟩ on 2017-09-15.
       If you discover any rendering problems in this HTML version of the
       page, or you believe there is a better or more up-to-date source for
       the page, or you have corrections or improvements to the information
       in this COLOPHON (which is not part of the original manual page),
       send a mail to man-pages@man7.org

                          Version 487: 25 Oct 2016                   LESS(1)

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