less

Page through text one screenful at a time. Less is a program similar to more, but which allows backward movement in the file as well as forward movement.

Syntax

       less [-[+]aBcCdeEfFgGiIJmMnNqQrRsSuUVwWX~]
	    [-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]...
       less -?
       less --help
       less -V
       less --version

Options - The options above are described in full on this page

Commands

In the following descriptions, ^X means control-X. ESC stands for the ESCAPE key; for example ESC-v means the two character sequence "ESCAPE", then "v".

   h or H    Help: display a summary of these commands. If you forget all
	                the other commands, remember this one.

   SPACE or ^V or f or ^F
	      Scroll forward N	lines,	default	 one  window  (see  option  -z
	      below).	If  N  is  more	 than  the screen size, only the final
	      screenful is displayed.  Warning: some systems use ^V as a  spe-
	      cial 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.

   RETURN or ^N or e or ^E or j or ^J
	      Scroll  forward N lines, default 1.  The entire N lines are dis-
	      played, 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 dis-
	      played, 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 com-
	      mands.  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 com-
	      mands.

   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.)

   g or < or ESC-<
	      Go to line N in the file, default 1 (beginning of file).	(Warn-
	      ing: 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.	(Warn-
	      ing:  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 char-
	      acters 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	 char-
	      acters  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.  Fol-
	      lowed 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 ' com-
	      mand 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 pat-
	      tern.  N defaults to 1.  The pattern is a regular expression, as
	      recognized by ed.	 The search starts at  the  second  line  dis-
	      played (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 cur-
		     rent screen, but don't move to the first match (KEEP cur-
		     rent position).

   ^R     Don't  interpret  regular expression metacharacters; that
		     is, do a simple textual comparison.

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

	      Certain characters are special as in the / command:
   ^N or !
		     Search for lines which do NOT match the pattern.

   ^E or *
		     Search multiple files.  That is, if  the  search  reaches
		     the  beginning  of	 the  current  file  without finding a
		     match, the search continues in the previous file  in  the
		     command line list.

   ^F or @
		     Begin the search at the last line of the last file in the
		     command line list, regardless of what is  currently  dis-
		     played  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  pat-
	      tern.   If the previous search was modified by ^N, the search is
	      made for the N-th line NOT containing the pattern.  If the  pre-
	      vious  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	cross-
	      ing 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  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  literal-
	      ization  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
	      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 let-
	      ters, 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 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.

Also: Options, Line editing and Language support

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.

“Counter to the widely held belief that industrial agriculture is more efficient and productive, small farms produce far more per acre than large farms” ~ Christos Vasilikiotis (University of California, Berkeley)

Related:

less man page - Apple.com
lesskey - specify key bindings for less
echo - Display message on screen
tee - Redirect output to multiple files
The less home page (Mark Nudelman)


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