SED(1)                                                     SED(1)

NAME
       sed - a Stream EDitor

SYNOPSIS
       sed [-n] [-V] [--quiet] [--silent] [--version] [--help]
           [-e script] [--expression=script]
           [-f script-file] [--file=script-file]
           [script-if-no-other-script]
           [file...]

DESCRIPTION
       Sed  is  a stream editor.  A stream editor is used to per-
       form basic text transformations on an input stream (a file
       or  input from a pipeline).  While in some ways similar to
       an editor which permits scripted edits (such as  ed),  sed
       works  by  making  only one pass over the input(s), and is
       consequently more efficient.  But it is sed's  ability  to
       filter text in a pipeline which particularly distinguishes
       it from other types of editors.

OPTIONS
       Sed  may  be  invoked  with  the  following   command-line
       options:

       -V

       --version
              Print  out the version of sed that is being run and
              a copyright notice, then exit.

       -h

       --help Print a usage  message  briefly  summarizing  these
              command-line options and the bug-reporting address,
              then exit.

       -n

       --quiet

       --silent
              By default, sed will print out the pattern space at
              the  end  of  each cycle through the script.  These
              options disable this automatic  printing,  and  sed
              will  only  produce  output when explicitly told to
              via the p command.

       -e script

       --expression=script
              Add the commands in script to the set  of  commands
              to be run while processing the input.

       -f script-file

       --file=script-file
              Add  the commands contained in the file script-file
              to the set of commands to be run  while  processing
              the input.

       If  no  -e,-f,--expression, or --file options are given on
       the command-line, then the first  non-option  argument  on
       the command line is taken to be the script to be executed.

       If any command-line parameters remain after processing the
       above,  these  parameters  are interpreted as the names of
       input files to be processed.  A file name of -  refers  to
       the  standard  input stream.  The standard input will pro-
       cessed if no file names are specified.

Command Synopsis
       This is just a brief synopsis of sed commands to serve  as
       a reminder to those who already know sed; other documenta-
       tion (such as the texinfo document) must be consulted  for
       fuller descriptions.

   Zero-address ``commands''
       : label
              Label for b and t commands.

       #comment
              The  comment extends until the next newline (or the
              end of a -e script fragment).

       }      The closing bracket of a { } block.

   Zero- or One- address commands
       =      Print the current line number.

       a \

       text   Append text, which has each embedded  newline  pre-
              ceeded by a backslash.

       i \

       text   Insert  text,  which has each embedded newline pre-
              ceeded by a backslash.

       q      Immediately quit the sed script without  processing
              any  more  input,  except that if auto-print is not
              diabled the current pattern space will be  printed.

       r filename
              Append text read from filename.

   Commands which accept address ranges
       {      Begin a block of commands (end with a }).

       b label
              Branch to label; if label is omitted, branch to end
              of script.

       t label
              If a s/// has done a successful substitution  since
              the  last  input line was read and since the last t
              command, then branch to label; if label is omitted,
              branch to end of script.

       c \

       text   Replace  the  selected  lines  with text, which has
              each embedded newline preceeded by a backslash.

       d      Delete pattern space.  Start next cycle.

       D      Delete up to the first embedded newline in the pat-
              tern  space.   Start  next  cycle, but skip reading
              from the input if there is still data in  the  pat-
              tern space.

       h H    Copy/append pattern space to hold space.

       g G    Copy/append hold space to pattern space.

       x      Exchange  the  contents  of  the  hold  and pattern
              spaces.

       l      List out the current line in a ``visually unambigu-
              ous'' form.

       n N    Read/append the next line of input into the pattern
              space.

       p      Print the current pattern space.

       P      Print up to the first embedded newline of the  cur-
              rent pattern space.

       s/regexp/replacement/
              Attempt  to match regexp against the pattern space.
              If successful, replace that  portion  matched  with
              replacement.   The replacement may contain the spe-
              cial character & to refer to that  portion  of  the
              pattern   space  which  matched,  and  the  special
              escapes \1 through \9 to refer to the corresponding
              matching sub-expressions in the regexp.

       w      filename  Write  the current pattern space to file-
              name.

       y/source/dest/
              Transliterate the characters in the  pattern  space
              which appear in source to the corresponding charac-
              ter in dest.

Addresses
       Sed commands can be given with no addresses, in which case
       the command will be executed for all input lines; with one
       address, in which case the command will only  be  executed
       for  input  lines  which  match  that address; or with two
       addresses, in which case the command will be executed  for
       all  input  lines which match the inclusive range of lines
       starting from the first address and continuing to the sec-
       ond  address.   Three things to note about address ranges:
       the syntax is addr1,addr2 (i.e., the addresses  are  sepa-
       rated  by  a  comma);  the  line  which addr1 matched will
       always be accepted, even if addr2 selects an earlier line;
       and  if  addr2  is a regexp, it will not be tested against
       the line that addr1 matched.

       After the address (or address-range), and before the  com-
       mand,  a !  may be inserted, which specifies that the com-
       mand shall only be executed if the  address  (or  address-
       range) does not match.

       The following address types are supported:

       number Match only the specified line number.

       first~step
              Match  every step'th line starting with line first.
              For example, ``sed -n 1~2p''  will  print  all  the
              odd-numbered  lines  in  the  input stream, and the
              address 2~5 will match every fifth  line,  starting
              with the second.  (This is a GNU extension.)

       $      Match the last line.

       /regexp/
              Match lines matching the regular expression regexp.

       \cregexpc
              Match lines matching the regular expression regexp.
              The c may be any character.

Regular expressions
       POSIX.2  BREs  should  be  supported, but they aren't com-
       pletely yet.  The \n  sequence  in  a  regular  expression
       matches  the  newline  character.  There are also some GNU
       extensions.  [XXX FIXME: more needs to be  said.   At  the
       very   least,   a  reference  to  another  document  which
       describes what is supported should be given.]

Miscellaneous notes
       This version of sed supports a \<newline> sequence in  all
       regular  expressions, the replacement part of a substitute
       (s) command, and  in  the  source  and  dest  parts  of  a
       transliterate  (y)  command.   The  \ is stripped, and the
       newline is kept.

SEE ALSO
       awk(1), ed(1), expr(1), emacs(1), perl(1),  tr(1),  vi(1),
       regex(5) [well, one ought to be written... XXX], sed.info,
       any of various books on sed, the sed FAQ
       (http://www.wollery.demon.co.uk/sedtut10.txt,
       http://www.ptug.org/sed/sedfaq.htm).

BUGS
       E-mail bug reports to bug-gnu-utils@gnu.org.  Be sure to
       include the word ``sed'' somewhere in the ``Subject:''
       field.

GNU Project                 1998-05-07                          1