glenda.party
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term% cat index.txt
SED(1)                      General Commands Manual                     SED(1)



NAME
       sed - stream editor

SYNOPSIS
       sed [ -n ] [ -g ] [ -e script ] [ -f sfile ] [ file ...  ]

DESCRIPTION
       Sed  copies  the  named  files (standard input default) to the standard
       output, edited according to a script of commands.  The -f option causes
       the  script  to be taken from file sfile; these options accumulate.  If
       there is just one -e option and no -f's, the flag -e  may  be  omitted.
       The  -n  option  suppresses the default output; -g causes all substitu‐
       tions to be global, as if suffixed g.

       A script consists of editing commands, one per line, of  the  following
       form:

              [address [, address] ] function [argument ...]

       In  normal  operation sed cyclically copies a line of input into a pat‐
       tern space (unless there is something left after a command), applies in
       sequence all commands whose addresses select that pattern space, and at
       the end of the script copies the pattern space to the  standard  output
       (except under -n) and deletes the pattern space.

       An  address  is either a decimal number that counts input lines cumula‐
       tively across files, a that addresses the last line of input, or a con‐
       text address, /regular-expression/, in the style of regexp(6), with the
       added convention that matches a newline embedded in the pattern space.

       A command line with no addresses selects every pattern space.

       A command line with one address selects each pattern space that matches
       the address.

       A  command line with two addresses selects the inclusive range from the
       first pattern space that matches the first  address  through  the  next
       pattern  space  that  matches  the second.  (If the second address is a
       number less than or equal to the line number first selected,  only  one
       line  is  selected.)  Thereafter the process is repeated, looking again
       for the first address.

       Editing commands can be applied to non-selected pattern spaces  by  use
       of the negation function (below).

       An  argument  denoted  text  consists of one or more lines, all but the
       last of which end with to hide the newline.  Backslashes  in  text  are
       treated  like  backslashes in the replacement string of an command, and
       may be used to protect initial blanks and tabs  against  the  stripping
       that is done on every script line.

       An  argument denoted rfile or wfile must terminate the command line and
       must be preceded by exactly one blank.  Each wfile  is  created  before
       processing begins.  There can be at most 120 distinct wfile arguments.

       a\
       text         Append.   Place text on the output before reading the next
                    input line.

       b label      Branch to the : command bearing the label.   If  label  is
                    empty, branch to the end of the script.

       c\
       text         Change.  Delete the pattern space.  With 0 or 1 address or
                    at the end of a 2-address range, place text on the output.
                    Start the next cycle.

       d            Delete the pattern space.  Start the next cycle.

       D            Delete  the  initial  segment of the pattern space through
                    the first newline.  Start the next cycle.

       g            Replace the contents of the pattern space by the  contents
                    of the hold space.

       G            Append  the  contents  of  the  hold  space to the pattern
                    space.

       h            Replace the contents of the hold space by the contents  of
                    the pattern space.

       H            Append  the  contents  of  the  pattern  space to the hold
                    space.

       i\
       text         Insert.  Place text on the standard output.

       n            Copy the pattern space to the  standard  output.   Replace
                    the pattern space with the next line of input.

       N            Append the next line of input to the pattern space with an
                    embedded newline.  (The current line number changes.)

       p            Print.  Copy the pattern space to the standard output.

       P            Copy the initial segment of the pattern space through  the
                    first newline to the standard output.

       q            Quit.   Branch  to  the end of the script.  Do not start a
                    new cycle.

       r rfile      Read the contents of rfile.  Place them on the output  be‐
                    fore reading the next input line.

       s/regular-expression/replacement/flags
                    Substitute  the  replacement  string  for instances of the
                    regular-expression in the pattern  space.   Any  character
                    may  be  used instead of For a fuller description see reg‐
                    exp(6).  Flags is zero or more of

                    g      Global.  Substitute  for  all  non-overlapping  in‐
                           stances  of the regular expression rather than just
                           the first one.

                    p      Print the pattern space if a replacement was made.

                    w wfile
                           Write.  Append the pattern space to wfile if a  re‐
                           placement was made.

       t label      Test.  Branch to the command bearing the label if any sub‐
                    stitutions have been made since the most recent reading of
                    an  input line or execution of a If label is empty, branch
                    to the end of the script.

       w            wfile
                    Write.  Append the pattern space to wfile.

       x            Exchange the contents of the pattern and hold spaces.

       y/string1/string2/
                    Transform.   Replace  all  occurrences  of  characters  in
                    string1  with the corresponding character in string2.  The
                    lengths of string1 and string2 must be equal.

       !function    Don't.  Apply the function (or group, if function is  only
                    to lines not selected by the address(es).

       : label      This  command  does  nothing; it bears a label for b and t
                    commands to branch to.

       =            Place the current line number on the standard output as  a
                    line.

       {            Execute  the  following  commands  through a matching only
                    when the pattern space is selected.

                    An empty command is ignored.

EXAMPLES
       sed 10q file
              Print the first 10 lines of the file.

       sed '/^$/d'
              Delete empty lines from standard input.

       sed 's/UNIX/& system/g'
              Replace every instance of by

       sed 's/ *$//   drop trailing blanks
       /^$/d               drop empty lines
       s/  */\        replace blanks by newlines
       /g
       /^$/d' chapter*
              Print the files chapter1, chapter2, etc. one word to a line.

       nroff -ms manuscript | sed '
       ${
            /^$/p          if last line of file is empty, print it
       }
       //N            if current line is empty, append next line
       /^\n$/D'       if two lines are empty, delete the first
              Delete all but one of each group of empty lines from a formatted
              manuscript.

SOURCE
       /sys/src/cmd/sed.c

SEE ALSO
       ed(1), grep(1), awk(1), lex(1), sam(1), regexp(6)
       L.  E.  McMahon,  `SED  — A Non-interactive Text Editor', Unix Research
       System Programmer's Manual, Volume 2.

BUGS
       If input is from a pipe, buffering may consume characters beyond a line
       on which a command is executed.



                                                                        SED(1)