SED(1)                     Commands and Applications                    SED(1)




NAME

       sed - stream editor


SYNOPSIS

       sed command [-an] [file ...]

       sed [-an] [-e command]...  [-f command_file]...  [file ...]


DESCRIPTION

       The  sed utility reads the specified files, or the standard input if no
       files are specified, modifying the input as specified by a list of com-
       mands.  The input is then written to the standard output.

       A single command may be specified as the first argument to sed.  Multi-
       ple commands may be specified by using the -e or -f options.  All  com-
       mands  are applied to the input in the order they are specified regard-
       less of their origin.

       The following options are available:

       -a     The files listed as parameters for the w (write)  functions  are
              created (or truncated) before any processing begins, by default.
              The -a option causes sed to delay opening each file until a com-
              mand  containing  the related w function is applied to a line of
              input.

       -e command
              Append the editing commands specified by the command argument to
              the list of commands.

       -f command_file
              Append  the  editing  commands found in the file command_file to
              the list of commands.   The  editing  commands  should  each  be
              listed on a separate line.

       -n     By  default, each line of input is echoed to the standard output
              after all of the commands have  been  applied  to  it.   The  -n
              option suppresses this behavior.

       The form of a sed command is as follows:

       [address [, address]] function [arguments]

       Whitespace  may  be  inserted before the first address and the function
       portions of the command.

       Normally, sed cyclically copies a line of input, not including its ter-
       minating  newline  character,  into  a  pattern space, (unless there is
       something left after a D function), applies all of  the  commands  with
       addresses  that  select that pattern space, copies the pattern space to
       the standard output, appending  a  newline,  and  deletes  the  pattern
       space.

       Some  of the functions use a hold space to save all or part of the pat-
       tern space for subsequent retrieval.


Sed Addresses

       An address is not required, but if specified must  be  a  number  (that
       counts input lines cumulatively across input files), a dollar ($) char-
       acter that addresses the last line  of  input,  or  a  context  address
       (which  consists  of  a  regular  expression preceded and followed by a
       delimiter).

       A command line with no addresses selects every pattern space.

       A command line with one address selects all of the pattern spaces  that
       match 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  that
       line  is  selected.)  Starting at the first line following the selected
       range, sed starts looking again for the first address.

       Editing commands can be applied to non-selected pattern spaces  by  use
       of the exclamation character (!)  function.


Sed Regular Expressions

       The  sed  regular expressions are basic regular expressions (BRE's, see
       regex(3) for more information).  In addition, sed has the following two
       additions to BRE's:

       In  a  context address, any character other than a backslash (\f[R]) or
              newline character may be used to delimit the regular expression.
              Also,  putting a backslash character before the delimiting char-
              acter causes the character to be treated literally.   For  exam-
              ple,  in the context address \xabc\xdefx, the RE delimiter is an
              x and the second x  stands  for  itself,  so  that  the  regular
              expression is abcxdef.

       The escape sequence \n matches a newline character embedded in the pat-
              tern space.  You can't, however, use a literal newline character
              in an address or in the substitute command.

       One special feature of sed regular expressions is that they can default
       to the last regular expression used.  If a regular expression is empty,
       i.e.  just  the  delimiter  characters  are specified, the last regular
       expression encountered is used instead.  The last regular expression is
       defined  as  the  last regular expression used as part of an address or
       substitute command, and at run-time, not  compile-time.   For  example,
       the command /abc/s//XXX/ will substitute XXX for the pattern abc.


Sed Functions

       In  the  following  list of commands, the maximum number of permissible
       addresses for  each  command  is  indicated  by  [0addr],  [1addr],  or
       [2addr], representing zero, one, or two addresses.

       The argument text consists of one or more lines.  To embed a newline in
       the text, precede it with a backslash.  Other backslashes in  text  are
       deleted and the following character taken literally.

       The  r and w functions take an optional file parameter, which should be
       separated from the function letter by white space.  Each file given  as
       an  argument  to  sed is created (or its contents truncated) before any
       input processing begins.

       The b, r, s, t, w, y, !, and : functions all  accept  additional  argu-
       ments.  The following synopses indicate which arguments have to be sep-
       arated from the function letters by white space characters.

       Two of the functions take a function-list.  This is a list of sed func-
       tions separated by newlines, as follows:

               -literal -offset indent
              { function
                function
                ...
                function
              }

       The  {  can  be  preceded  by  white space and can be followed by white
       space.  The function can be preceded by white space.  The terminating }
       must be preceded by a newline or optional white space.

       [2addr]function-list
              Execute function-list only when the pattern space is selected.

       [1addr]a.ft R

       text   Write text to standard output immediately before each attempt to
              read a line of input, whether by executing the N function or  by
              beginning a new cycle.

       [2addr]b [label]
              Branch to the : function with the specified label.  If the label
              is not specified, branch to the end of the script.

       [2addr]c.ft R

       text   Delete the pattern space.  With 0 or 1 address or at the end  of
              a 2-address range, text is written to the standard output.

       [2addr]d
              Delete the pattern space and start the next cycle.

       [2addr]D
              Delete  the  initial  segment  of  the pattern space through the
              first newline character and start the next cycle.

       [2addr]g
              Replace the contents of the pattern space with the  contents  of
              the hold space.

       [2addr]G
              Append  a newline character followed by the contents of the hold
              space to the pattern space.

       [2addr]h
              Replace the contents of the hold space with the contents of  the
              pattern space.

       [2addr]H
              Append  a newline character followed by the contents of the pat-
              tern space to the hold space.

       [1addr]i.ft R

       text
              Write text to the standard output.

       [2addr]l
              (The letter ell.)  Write the pattern space to the standard  out-
              put in a visually unambiguous form.  This form is as follows:
              backslash       \\
              alert           \a
              form-feed       \f
              newline         \n
              carriage-return \r
              tab             \t
              vertical tab    \v

       Nonprintable  characters are written as three-digit octal numbers (with
       a preceding backslash) for each byte in the character (most significant
       byte  first).   Long  lines are folded, with the point of folding indi-
       cated by displaying a backslash followed by a newline.  The end of each
       line is marked with a $.

       [2addr]n
              Write  the  pattern  space to the standard output if the default
              output has not been suppressed, and replace  the  pattern  space
              with the next line of input.

       [2addr]N
              Append  the  next  line  of input to the pattern space, using an
              embedded newline character to  separate  the  appended  material
              from  the  original contents.  Note that the current line number
              changes.

       [2addr]p
              Write the pattern space to standard output.

       [2addr]P
              Write the pattern space, up to the first  newline  character  to
              the standard output.

       [1addr]q
              Branch  to the end of the script and quit without starting a new
              cycle.

       [1addr]r file
              Copy the contents of file to  the  standard  output  immediately
              before the next attempt to read a line of input.  If file cannot
              be read for any reason, it is silently ignored and no error con-
              dition is set.

       [2addr]s/ regular expression/replacement/flags
              Substitute  the replacement string for the first instance of the
              regular expression in the pattern space.   Any  character  other
              than  backslash  or  newline  can  be used instead of a slash to
              delimit the RE and the  replacement.   Within  the  RE  and  the
              replacement,  the  RE  delimiter itself can be used as a literal
              character if it is preceded by a backslash.

       An ampersand (&) appearing in the replacement is replaced by the string
              matching  the  RE.  The special meaning of & in this context can
              be suppressed by preceding it by a backslash.  The string .ft  R
              where  # is a digit, is replaced by the text matched by the cor-
              responding backreference expression (see re_format(7)).

       A line can be split by substituting a newline character  into  it.   To
              specify  a  newline character in the replacement string, precede
              it with a backslash.

       The value of flags in the substitute function is zero or  more  of  the
              following:
              Make  the substitution only for the N'th occurrence of the regu-
              lar expression in the pattern space.
       Make the substitution for all non-overlapping matches  of  the  regular
       expression, not just the first one.
       Write  the  pattern space to standard output if a replacement was made.
       If the replacement string is identical to that which it replaces, it is
       still considered to have been a replacement.
       Append  the  pattern  space  to file if a replacement was made.  If the
       replacement string is identical to that which it replaces, it is  still
       considered to have been a replacement.

       [2addr]t [label]
              Branch  to the : function bearing the label if any substitutions
              have been made since the most recent reading of an input line or
              execution  of a t function.  If no label is specified, branch to
              the end of the script.

       [2addr]w file
              Append the pattern space to the file.

       [2addr]x
              Swap the contents of the pattern and hold spaces.

       [2addr]y/string1/string2/
              Replace all occurrences of characters in string1 in the  pattern
              space with the corresponding characters from string2.  Any char-
              acter other than a backslash or newline can be used instead of a
              slash  to  delimit  the  strings.  Within string1 and string2, a
              backslash followed by any character other than a newline is that
              literal  character,  and  a  backslash  followed  by an ''n'' is
              replaced by a newline character.

       [2addr]!function

       [2addr]!function-list
              Apply the function or function-list only to the lines  that  are
              not selected by the address(es).

       [0addr]:label
              This  function does nothing; it bears a label to which the b and
              t commands may branch.

       [1addr]=
              Write the line number to the standard output followed by a  new-
              line character.

       [0addr]
              Empty lines are ignored.

       [0addr]#
              The  #  and  the remainder of the line are ignored (treated as a
              comment), with the single exception that if the first two  char-
              acters  in  the  file  are #n, the default output is suppressed.
              This is the same as specifying the  -n  option  on  the  command
              line.

       The sed utility exits 0 on success and >0 if an error occurs.


VERSION

       This manual page documents sed version 2.0 for GNO/ME.


SEE ALSO

       awk(1), ed(1), grep(1), regex(3), re_format(7)


ATTRIBUTIONS

       This  command was ported from FreeBSD source code for distribution with
       GNO/ME 2.0.6.


HISTORY

       An implementation of sed for the Apple IIGS was  written  in  1990  and
       distributed separately from GNO.


STANDARDS

       The sed function is expected to be a superset of the POSIX.2 specifica-
       tion.



GNO                              November 1997                          SED(1)

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