path: root/contrib/less/less.man

LESS(1)                                                   LESS(1)


NNAAMMEE
       less - opposite of more

SSYYNNOOPPSSIISS
       lleessss --??
       lleessss ----hheellpp
       lleessss --VV
       lleessss ----vveerrssiioonn
       lleessss [[--[[++]]aaBBccCCddeeEEffFFggGGiiIIJJmmMMnnNNqqQQrrRRssSSuuUUVVwwWWXX]]
            [[--bb _b_u_f_s]] [[--hh _l_i_n_e_s]] [[--jj _l_i_n_e]] [[--kk _k_e_y_f_i_l_e]]
            [[--{{ooOO}} _l_o_g_f_i_l_e]] [[--pp _p_a_t_t_e_r_n]] [[--PP _p_r_o_m_p_t]] [[--tt _t_a_g]]
            [[--TT _t_a_g_s_f_i_l_e]] [[--xx _t_a_b,,......]] [[--yy _l_i_n_e_s]] [[--[[zz]] _l_i_n_e_s]]
            [[++[[++]]_c_m_d]] [[----]] [[_f_i_l_e_n_a_m_e]]......
       (See  the OPTIONS section for alternate option syntax with
       long option names.)


DDEESSCCRRIIPPTTIIOONN
       _L_e_s_s is a program similar to _m_o_r_e (1),  but  which  allows
       backward movement in the file as well as forward movement.
       Also, _l_e_s_s does not have to read  the  entire  input  file
       before  starting,  so  with large input files it starts up
       faster than text editors like _v_i (1).  _L_e_s_s  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 _m_o_r_e and _v_i_.  Commands may be
       preceded by a decimal number, called N in the descriptions
       below.  The number is used by some commands, as indicated.


CCOOMMMMAANNDDSS
       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.  Warn­
              ing: some systems use ^V as a  special  literaliza­
              tion 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



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LESS(1)                                                   LESS(1)


              it reaches end-of-file in the process.

       RETURN or ^N or e or ^E or j or ^J
              Scroll  forward  N  lines, default 1.  The entire N
              lines are displayed, even if N  is  more  than  the
              screen size.

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

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

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

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

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

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

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

       r or ^R or ^L
              Repaint the screen.

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

       F      Scroll  forward,  and  keep trying to read when the
              end of file  is  reached.   Normally  this  command



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LESS(1)                                                   LESS(1)


              would  be used when already at the end of the file.
              It is a way to monitor the tail of a file which  is
              growing while it is being viewed.  (The behavior is
              similar to the "tail -f" command.)

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

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

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

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

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

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

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

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

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

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

       ESC-^B Followed by two characters, acts like },  but  uses
              the  two  characters  as  open  and close brackets,



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LESS(1)                                                   LESS(1)


              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 con­
              taining the pattern.  N defaults to 1.  The pattern
              is  a regular expression, as recognized by _e_d_.  The
              search starts at the second line displayed (but see
              the -a and -j options, which change this).

              Certain  characters  are  special if entered at the
              beginning of the pattern; they modify the  type  of
              search rather than become part of the pattern:

              ^N or !
                     Search for lines which do NOT match the pat­
                     tern.

              ^E or *
                     Search multiple  files.   That  is,  if  the
                     search  reaches  the END of the current file
                     without finding a match, the search  contin­
                     ues  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, regard­
                     less 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 metachar­
                     acters;   that   is,  do  a  simple  textual



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                     comparison.

       ?pattern
              Search backward in the file for the N-th line  con­
              taining the pattern.  The search starts at the line
              immediately before the top line displayed.

              Certain characters are special as in the / command:

              ^N or !
                     Search for lines which do NOT match the pat­
                     tern.

              ^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 com­
                     mand line list.

              ^F or @
                     Begin the search at the  last  line  of  the
                     last  file in the command line list, regard­
                     less 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 modi­
              fied 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 direc­
              tion.

       ESC-n  Repeat previous search, but  crossing  file  bound­
              aries.   The  effect  is  as if the previous search
              were modified by *.



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LESS(1)                                                   LESS(1)


       ESC-N  Repeat previous search, but in the  reverse  direc­
              tion and crossing file boundaries.

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

       :e [filename]
              Examine a new file.  If the  filename  is  missing,
              the  "current"  file  (see  the  :n and :p commands
              below) from the list of files in the  command  line
              is re-examined.  A percent sign (%) in the filename
              is replaced by the name of  the  current  file.   A
              pound  sign (#) is replaced by the name of the pre­
              viously 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.  Simi­
              larly, 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 spe­
              cial  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



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LESS(1)                                                   LESS(1)


              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 imme­
              diately after the dash, the setting of  the  option
              is  changed  but  no  message  is  printed.  If the
              option letter has a numeric value (such  as  -b  or
              -h),  or  a  string value (such as -P or -t), a new
              value may be entered after the option  letter.   If
              no  new  value is entered, a message describing the
              current setting is printed and nothing is  changed.

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

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

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

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

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

       _      (Underscore.)   Followed by one of the command line
              option letters, this will print a message  describ­
              ing  the  current  setting  of  that  option.   The



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LESS(1)                                                   LESS(1)


              setting of the option is not changed.

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

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

       V      Prints the version number of _l_e_s_s being run.

       q or Q or :q or :Q or ZZ
              Exits _l_e_s_s_.

       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  environ­
              ment  variable  SHELL, or defaults to "sh".  On MS-
              DOS and OS/2 systems, the shell is the normal  com­
              mand 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.





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LESS(1)                                                   LESS(1)


OOPPTTIIOONNSS
       Command line options are described  below.   Most  options
       may be changed while _l_e_s_s 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 abbrevi­
       ated  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  capital­
       ized;  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 _l_e_s_s is invoked, you might tell _c_s_h_:

       setenv LESS "-options"

       or if you use _s_h_:

       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  environ­
       ment 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 "-+".

       For options like -P or -D which take a following string, a
       dollar sign ($) must be used to  signal  the  end  of  the
       string.  For example, to set two -D options on MS-DOS, you
       must have a dollar sign between them, like this:

       LESS="-Dn9.1$-Ds4.1"


       -? or --help
              This option displays  a  summary  of  the  commands
              accepted  by  _l_e_s_s  (the  same  as  the h command).
              (Depending on how your shell interprets  the  ques­
              tion  mark,  it may be necessary to quote the ques­
              tion mark, thus: "-\?".)

       -a or --search-skip-screen
              Causes searches to start after the last  line  dis­
              played  on  the  screen,  thus  skipping  all lines



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LESS(1)                                                   LESS(1)


              displayed on  the  screen.   By  default,  searches
              start  at  the  second line on the screen (or after
              the last found line; see the -j option).

       -b_n or --buffers=_n
              Specifies the number of buffers _l_e_s_s will  use  for
              each  file.   Buffers  are  1K,  and  by default 10
              buffers are used for each file (except if the  file
              is a pipe; see the -B option).  The number _n speci­
              fies a different number of buffers to use.

       -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  the number of
              buffers specified by the -b option are used.  Warn­
              ing:  use  of  -B  can result in erroneous display,
              since only the most recently  viewed  part  of  the
              file is kept in memory; any earlier data is lost.

       -c or --clear-screen
              Causes  full screen repaints to be painted from the
              top line down.  By default,  full  screen  repaints
              are  done  by  scrolling  from  the  bottom  of the
              screen.

       -C or --CLEAR-SCREEN
              The -C option is like -c, but the screen is cleared
              before it is repainted.

       -d or --dumb
              The -d option suppresses the error message normally
              displayed if the terminal is dumb; that  is,  lacks
              some  important  capability, such as the ability to
              clear the screen or scroll backward.  The -d option
              does not otherwise change the behavior of _l_e_s_s on a
              dumb terminal).

       -Dxx_c_o_l_o_r or --color=xx_c_o_l_o_r
              [MS-DOS only] Sets the color of the text displayed.
              xx  is  a single character which selects the type of
              text whose color is being set:  n=normal,  s=stand­
              out,  d=bold,  u=underlined,  k=blink.   _c_o_l_o_r is a
              pair of numbers separated by a period.   The  first
              number  selects the foreground color and the second
              selects the background color of the text.  A single
              number _N is the same as _N_._0.

       -e or --quit-at-eof
              Causes  _l_e_s_s  to automatically exit the second time
              it reaches end-of-file.  By default, the  only  way



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              to exit _l_e_s_s is via the "q" command.

       -E or --QUIT-AT-EOF
              Causes _l_e_s_s to automatically exit the first time it
              reaches end-of-file.

       -f or --force
              Forces non-regular files to be opened.  (A non-reg­
              ular file is a directory or a device special file.)
              Also suppresses the warning message when  a  binary
              file  is  opened.   By default, _l_e_s_s will refuse to
              open non-regular files.

       -F or --quit-if-one-screen
              Causes _l_e_s_s to automatically  exit  if  the  entire
              file can be displayed on the first screen.

       -g or --hilite-search
              Normally,  _l_e_s_s  will  highlight  ALL strings which
              match the  last  search  command.   The  -g  option
              changes this behavior to highlight only the partic­
              ular string which was found by the last search com­
              mand.   This  can cause _l_e_s_s to run somewhat faster
              than the default.

       -G or --HILITE-SEARCH
              The  -G  option  suppresses  all  highlighting   of
              strings found by search commands.

       -h_n or ---max-back-scroll=_n
              Specifies a maximum number of lines to scroll back­
              ward.  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  pat­
              tern contains uppercase letters.

       -j_n or --jump-target=_n
              Specifies  a  line on the screen where the "target"
              line is to be positioned.  A  target  line  is  the
              object of a text search, tag search, jump to a line
              number, jump to a file percentage,  or  jump  to  a
              marked position.  The screen line is specified by a



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LESS(1)                                                   LESS(1)


              number: the top line on the screen is 1,  the  next
              is  2,  and  so  on.  The number may be negative to
              specify a  line  relative  to  the  bottom  of  the
              screen:  the  bottom  line on the screen is -1, the
              second to the bottom is -2, and so on.  If  the  -j
              option  is used, searches begin at the line immedi­
              ately after the target line.  For example, if "-j4"
              is  used, the target line is the fourth line on the
              screen, so searches begin at the fifth line on  the
              screen.

       -J or --status-column
              Displays  a  status  column at the left edge of the
              screen.  The status column  shows  the  lines  that
              matched  the  current search.  The status column is
              also used if the -w or -W option is in effect.

       -k_f_i_l_e_n_a_m_e or --lesskey-file=_f_i_l_e_n_a_m_e
              Causes _l_e_s_s to open and interpret the named file as
              a  _l_e_s_s_k_e_y  (1)  file.   Multiple -k options may be
              specified.  If the LESSKEY or LESSKEY_SYSTEM  envi­
              ronment  variable  is  set, or if a lesskey file is
              found in a standard place (see KEY BINDINGS), it is
              also used as a _l_e_s_s_k_e_y file.

       -m or --long-prompt
              Causes  _l_e_s_s  to prompt verbosely (like _m_o_r_e), with
              the  percent  into  the  file.   By  default,  _l_e_s_s
              prompts with a colon.

       -M or --LONG-PROMPT
              Causes  _l_e_s_s  to  prompt  even  more verbosely than
              _m_o_r_e_.

       -n or --line-numbers
              Suppresses line numbers.  The default (to use  line
              numbers)  may cause _l_e_s_s 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  begin­
              ning of each line in the display.

       -o_f_i_l_e_n_a_m_e or --log-file=_f_i_l_e_n_a_m_e
              Causes  _l_e_s_s 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, _l_e_s_s will ask for confirmation



                     Version 371: 26 Dec 2001                  12





LESS(1)                                                   LESS(1)


              before overwriting it.

       -O_f_i_l_e_n_a_m_e or --LOG-FILE=_f_i_l_e_n_a_m_e
              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 _l_e_s_s 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 _l_e_s_s_.

       -p_p_a_t_t_e_r_n or --pattern=_p_a_t_t_e_r_n
              The -p option on the command line is equivalent  to
              specifying  +/_p_a_t_t_e_r_n;  that  is,  it tells _l_e_s_s to
              start at the first occurrence  of  _p_a_t_t_e_r_n  in  the
              file.

       -P_p_r_o_m_p_t or --prompt=_p_r_o_m_p_t
              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  _l_e_s_s  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



                     Version 371: 26 Dec 2001                  13





LESS(1)                                                   LESS(1)


              option  is  used,  _l_e_s_s  cannot  keep  track of the
              actual appearance of the screen (since this depends
              on  how the screen responds to each type of control
              character).  Thus,  various  display  problems  may
              result, such as long lines being split in the wrong
              place.

       -R or --RAW-CONTROL-CHARS
              Like -r, but tries to  keep  track  of  the  screen
              appearance  where possible.  This works only if the
              input consists of normal  text  and  possibly  some
              ANSI  "color" escape sequences, which are sequences
              of the form:

                   ESC [ ... m

              where the "..." is zero or  more  characters  other
              than  "m".   For  the  purpose  of keeping track of
              screen appearance, all control characters  and  all
              ANSI color escape sequences are assumed to not move
              the cursor.  You can make _l_e_s_s think  that  charac­
              ters  other  than  "m"  can  end  ANSI color escape
              sequences  by  setting  the  environment   variable
              LESSANSIENDCHARS  to  the  list of characters which
              can end a color escape sequence.

       -s or --squeeze-blank-lines
              Causes consecutive blank lines to be squeezed  into
              a  single  blank line.  This is useful when viewing
              _n_r_o_f_f output.

       -S or --chop-long-lines
              Causes lines longer than the  screen  width  to  be
              chopped rather than folded.  That is, the remainder
              of a long line is simply discarded.  The default is
              to  fold long lines; that is, display the remainder
              on the next line.

       -t_t_a_g or --tag=_t_a_g
              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  exam­
              ple,  there  may be a file in the current directory
              called "tags", which was previously built by  _c_t_a_g_s
              (1)  or  an equivalent command.  If the environment
              variable LESSGLOBALTAGS is set, it is taken  to  be
              the  name  of a command compatible with _g_l_o_b_a_l (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
              _l_e_s_s  (using the - command) as a way of examining a
              new file.  The command ":t" is equivalent to speci­
              fying -t from within _l_e_s_s_.




                     Version 371: 26 Dec 2001                  14





LESS(1)                                                   LESS(1)


       -T_t_a_g_s_f_i_l_e or --tag-file=_t_a_g_s_f_i_l_e
              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 _l_e_s_s_.

       -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 high­
              lights 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.

       -x_n,... or --tabs=_n,...
              Sets tab stops.  If only one _n  is  specified,  tab
              stops  are set at multiples of _n.  If multiple val­
              ues 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,
              _-_x_9_,_1_7  will  set  tabs at positions 9, 17, 25, 33,



                     Version 371: 26 Dec 2001                  15





LESS(1)                                                   LESS(1)


              etc.  The default for _n is 8.

       -X or --no-init
              Disables sending  the  termcap  initialization  and
              deinitialization  strings to the terminal.  This is
              sometimes desirable if the deinitialization  string
              does   something  unnecessary,  like  clearing  the
              screen.

       --no-keypad
              Disables  sending  the  keypad  initialization  and
              deinitialization  strings to the terminal.  This is
              sometimes useful if the  keypad  strings  make  the
              numeric keypad behave in an undesirable manner.

       -y_n or --max-forw-scroll=_n
              Specifies  a maximum number of lines to scroll for­
              ward.  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 _m_o_r_e_.  If the number _n is negative,  it  indi­
              cates  _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 automati­
              cally changes to 36 lines.

       -"_c_c or --quotes=_c_c
              Changes  the  filename quoting character.  This may
              be necessary if you are trying to name a file which
              contains  both  spaces  and quote characters.  Fol­
              lowed 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 char­
              acter.  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



                     Version 371: 26 Dec 2001                  16





LESS(1)                                                   LESS(1)


              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 com­
              mands.  If the number specified is  zero,  it  sets
              the  default number of positions to one half of the
              screen width.

       --     A command line argument of "--" marks  the  end  of
              option arguments.  Any arguments following this are
              interpreted as filenames.  This can be useful  when
              viewing a file whose name begins with a "-" or "+".

       +      If a command line option begins with ++, the remain­
              der  of  that option is taken to be an initial com­
              mand to _l_e_s_s_.  For example, +G tells _l_e_s_s 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  dis­
              play 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.


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

       LEFTARROW [ ESC-h ]
              Move the cursor one space to the left.

       RIGHTARROW [ ESC-l ]
              Move the cursor one space to the right.

       ^LEFTARROW [ ESC-b or ESC-LEFTARROW ]
              (That  is,  CONTROL  and LEFTARROW simultaneously.)
              Move the cursor one word to the left.

       ^RIGHTARROW [ ESC-w or ESC-RIGHTARROW ]
              (That is, CONTROL and  RIGHTARROW  simultaneously.)



                     Version 371: 26 Dec 2001                  17





LESS(1)                                                   LESS(1)


              Move the cursor one word to the right.

       HOME [ ESC-0 ]
              Move the cursor to the beginning of the line.

       END [ ESC-$ ]
              Move the cursor to the end of the line.

       BACKSPACE
              Delete  the character to the left of the cursor, or
              cancel the command if the command line is empty.

       DELETE or [ ESC-x ]
              Delete the character under the cursor.

       ^BACKSPACE [ ESC-BACKSPACE ]
              (That is, CONTROL  and  BACKSPACE  simultaneously.)
              Delete the word to the left of the cursor.

       ^DELETE [ ESC-X or ESC-DELETE ]
              (That   is,  CONTROL  and  DELETE  simultaneously.)
              Delete the word under the cursor.

       UPARROW [ ESC-k ]
              Retrieve the previous command line.

       DOWNARROW [ ESC-j ]
              Retrieve the next command line.

       TAB    Complete the partial filename to the  left  of  the
              cursor.   If it matches more than one filename, the
              first match  is  entered  into  the  command  line.
              Repeated  TABs  will  cycle thru the other matching
              filenames.  If the completed filename is  a  direc­
              tory,  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 com­
              mand if the command line is  empty.   If  you  have
              changed  your  line-kill character in Unix to some­
              thing other than ^U, that character is used instead
              of ^U.



                     Version 371: 26 Dec 2001                  18





LESS(1)                                                   LESS(1)


KKEEYY BBIINNDDIINNGGSS
       You may define your own _l_e_s_s commands by using the program
       _l_e_s_s_k_e_y (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 _l_e_s_s_k_e_y to change the  line-editing
       keys (see LINE EDITING), and to set environment variables.
       If the environment variable LESSKEY is set, _l_e_s_s uses that
       as the name of the lesskey file.  Otherwise, _l_e_s_s looks in
       a standard place for the lesskey file:  On  Unix  systems,
       _l_e_s_s  looks  for  a lesskey file called "$HOME/.less".  On
       MS-DOS and Windows systems, _l_e_s_s looks for a lesskey  file
       called  "$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 sys­
       tems,   _l_e_s_s   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 _l_e_s_s_k_e_y 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,
       _l_e_s_s  uses  that  as  the  name of the system-wide lesskey
       file.  Otherwise, _l_e_s_s 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 _l_e_s_s
       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.


IINNPPUUTT PPRREEPPRROOCCEESSSSOORR
       You  may  define an "input preprocessor" for _l_e_s_s_.  Before
       _l_e_s_s 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, _l_e_s_s 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



                     Version 371: 26 Dec 2001                  19





LESS(1)                                                   LESS(1)


       name of the replacement file to its standard  output.   If
       the input preprocessor does not output a replacement file­
       name, _l_e_s_s 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 environ­
       ment  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 _l_e_s_s 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  origi­
       nal  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 _l_e_s_s 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 exe­
       cuted     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 _l_e_s_s_, rather than putting
       the data into a replacement file.  This avoids the need to
       decompress the entire file before starting to view it.  An



                     Version 371: 26 Dec 2001                  20





LESS(1)                                                   LESS(1)


       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
       _l_e_s_s 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 pre­
       processor is an input pipe.

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

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

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


NNAATTIIOONNAALL CCHHAARRAACCTTEERR SSEETTSS
       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 charac­
       ters  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 charac­
              ters, all chars with values between 32 and 126  are
              normal, and all others are binary.





                     Version 371: 26 Dec 2001                  21





LESS(1)                                                   LESS(1)


       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 LESS­
              CHARSET=IBM-1047 or LC_CTYPE=en_US in your environ­
              ment.

       koi8-r Selects a Russian character set.

       next   Selects  a  character set appropriate for NeXT com­
              puters.

       utf-8  Selects the UTF-8 encoding of the ISO 10646 charac­
              ter set.

       In  special cases, it may be desired to tailor _l_e_s_s to use
       a character set other than the  ones  definable  by  LESS­
       CHARSET.   In  this  case,  the environment variable LESS­
       CHARDEF can be used to define a character set.  It  should
       be set to a string where each character in the string rep­
       resents 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  repeti­
       tion.   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 neces­
       sarily represent any real character set.)

       This table shows the value of LESSCHARDEF which is equiva­
       lent 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.



                     Version 371: 26 Dec 2001                  22





LESS(1)                                                   LESS(1)


            latin1    8bcccbcc18b95.33b.
            next      8bcccbcc18b95.bb125.bb

       If neither LESSCHARSET nor LESSCHARDEF  is  set,  but  the
       string  "UTF-8"  is  found  in the LC_ALL, LC_TYPE or LANG
       environment variables, then the default character  set  is
       utf-8.

       If  that string is not found, but your system supports the
       _s_e_t_l_o_c_a_l_e interface, _l_e_s_s will use setlocale to  determine
       the character set.  setlocale is controlled by setting the
       LANG or LC_CTYPE environment variables.

       Finally, if the _s_e_t_l_o_c_a_l_e 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 vari­
       able.  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 LESS­
       BINFMT  is  "*u[%x]",  binary  characters are displayed in
       underlined  hexadecimal  surrounded  by   brackets.    The
       default if no LESSBINFMT is specified is "*s<%X>".


PPRROOMMPPTTSS
       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 ordi­
       nary 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:

       %b_X    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



                     Version 371: 26 Dec 2001                  23





LESS(1)                                                   LESS(1)


              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.

       %d_X    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 dis­
              cussion of the LESSEDIT feature below.

       %f     Replaced by the name of the current input file.

       %i     Replaced by the index of the current  file  in  the
              list of input files.

       %l_X    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.

       %p_X    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.

       %P_X    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 any­
              where.

       %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.



                     Version 371: 26 Dec 2001                  24





LESS(1)                                                   LESS(1)


       The format of the prompt string can be  changed  depending
       on certain conditions.  A question mark followed by a sin­
       gle character acts like an "IF": depending on the  follow­
       ing 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.

       ?b_X    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).

       ?d_X    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).

       ?l_X    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.

       ?p_X    True if the percent into the  current  input  file,
              based  on  byte  offsets,  of the specified line is
              known.

       ?P_X    True if the percent into the  current  input  file,
              based  on  line  numbers,  of the specified line is
              known.

       ?s     Same as "?B".




                     Version 371: 26 Dec 2001                  25





LESS(1)                                                   LESS(1)


       ?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 file­
       name  is  followed by the line number, if known, otherwise
       the percent if known, otherwise the byte offset if  known.
       Otherwise,  a  dash  is printed.  Notice how each question
       mark has a matching period, and how the % after the %pt is
       included literally by escaping it with a backslash.

       ?n?f%f .?m(file %i of %m) ..?e(END) ?x- Next\: %x..%t

       This  prints the filename if this is the first prompt in a
       file, followed by the "file N of N" message  if  there  is
       more than one input file.  Then, if we are at end-of-file,
       the string "(END)" is printed followed by the name of  the
       next  file, if there is one.  Finally, any trailing spaces
       are truncated.  This is the default  prompt.   For  refer­
       ence,  here are the defaults for the other two prompts (-m
       and -M respectively).  Each is broken into two lines  here
       for readability only.

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

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

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

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

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



                     Version 371: 26 Dec 2001                  26





LESS(1)                                                   LESS(1)


            %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 vari­
       able can be changed to modify this default.


SSEECCUURRIITTYY
       When the environment variable LESSSECURE is set to 1, _l_e_s_s
       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.


EENNVVIIRROONNMMEENNTT VVAARRIIAABBLLEESS
       Environment variables may be specified either in the  sys­
       tem  environment  as  usual, or in a _l_e_s_s_k_e_y (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.)




                     Version 371: 26 Dec 2001                  27





LESS(1)                                                   LESS(1)


       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 envi­
              ronment 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 _l_e_s_s automatically.

       LESSANSIENDCHARS
              Characters  which  are assumed to end an ANSI color
              escape sequence (default "m").

       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-post­
              processor.

       LESSECHO
              Name of the lessecho program (default  "lessecho").
              The  lessecho program is needed to expand metachar­
              acters, such as * and ?, in filenames on Unix  sys­
              tems.

       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 _g_l_o_b_a_l  (1)  command.   If  not
              set, global tags are not used.



                     Version 371: 26 Dec 2001                  28





LESS(1)                                                   LESS(1)


       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 "metachar­
              acters" by the shell.

       LESSMETAESCAPE
              Prefix which less will add before each  metacharac­
              ter  in  a  command  sent  to  the shell.  If LESS­
              METAESCAPE is an empty string, commands  containing
              metacharacters will not be passed to the shell.

       LESSOPEN
              Command line to invoke the (optional) input-prepro­
              cessor.

       LESSSECURE
              Runs less in "secure" mode.  See  discussion  under
              SECURITY.

       LESSSEPARATOR
              String  to be appended to a directory name in file­
              name completion.

       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.)

       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 _l_e_s_s is being run.

       VISUAL The name of the editor (used for the v command).


SSEEEE AALLSSOO
       lesskey(1)


WWAARRNNIINNGGSS
       The = command and prompts (unless changed  by  -P)  report
       the line numbers of the lines at the top and bottom of the



                     Version 371: 26 Dec 2001                  29





LESS(1)                                                   LESS(1)


       screen, but the byte and percent of the line after the one
       at the bottom of the screen.

       If  the :e command is used to name more than one file, and
       one of the named files has been viewed previously, the new
       files may be entered into the list in an unexpected order.

       On certain older terminals (the so-called  "magic  cookie"
       terminals),  search  highlighting  will cause an erroneous
       display.  On such terminals, search highlighting  is  dis­
       abled by default to avoid possible problems.

       In  certain cases, when search highlighting is enabled and
       a search pattern begins with  a  ^,  more  text  than  the
       matching  string  may  be highlighted.  (This problem does
       not occur when less is compiled to use the  POSIX  regular
       expression package.)

       When  viewing  text containing ANSI color escape sequences
       using the -R option, searching will not find text contain­
       ing  an embedded escape sequence.  Also, search highlight­
       ing may change the color of some of the text which follows
       the highlighted text.

       On  some systems, _s_e_t_l_o_c_a_l_e claims that ASCII characters 0
       thru 31 are control characters rather than binary  charac­
       ters.   This  causes  _l_e_s_s  to  treat some binary files as
       ordinary, non-binary files.  To workaround  this  problem,
       set  the  environment  variable LESSCHARSET to "ascii" (or
       whatever character set is appropriate).

       See http://www.greenwoodsoftware.com/less for  the  latest
       list of known bugs in this version of less.


CCOOPPYYRRIIGGHHTT
       Copyright (C) 2001  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 war­
       ranty of  MERCHANTABILITY  or  FITNESS  FOR  A  PARTICULAR



                     Version 371: 26 Dec 2001                  30





LESS(1)                                                   LESS(1)


       PURPOSE.   See  the  GNU  General  Public License for more
       details.


AAUUTTHHOORR
       Mark Nudelman <markn@greenwoodsoftware.com>
       Send bug reports or comments to the above  address  or  to
       bug-less@gnu.org.
       For   more   information,   see   the   less  homepage  at
       http://www.greenwoodsoftware.com/less.















































                     Version 371: 26 Dec 2001                  31