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sed(1)			     General Commands Manual			  sed(1)

NAME
     sed - the 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.

     An  -e  option  supplies  a  single edit command from the next argument; if
     there are several of these they are executed in the order	in   which  they
     appear.  If  there  is just one -e option and no -f 's, the -e  flag may be
     omitted.

     An -f option causes commands to be taken from the file "sfile";   if  there
     are  several   of these they are  executed in the order  in  which they ap-
     pear; -e and -f commands may be mixed.

     The -g option causes sed to act as though every substitute  command in  the
     script has a g suffix.

     The -n option suppresses the default output.

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

	  [address [, address] ] function [arguments]

     Normally sed cyclically copies a line of input into a  current text buffer,
     then  applies  all  commands whose addresses select the buffer in sequence,
     then copies the buffer to standard output and clears it.

     The -n option suppresses normal output (so that only  p  and  w  output  is
     done).  Also, some commands (n, N) do their own line reads, and some others
     (d, D) cause all commands following in the script to be skipped (the D com-
     mand also suppresses the clearing of the current  text  buffer  that  would
     normally occur before the next cycle).

     It  is  also helpful to know that there's a second buffer (called the `hold
     space' that can be copied or appended to or from or swapped with  the  cur-
     rent text buffer.

     An  address  is: a decimal numeral (which matches the line it numbers where
     line numbers start at 1 and run cumulatively across files), or a  `$'  that
     addresses	the last line of input, or a context address, which is a `/regu-
     lar expression/', in the style of ed (1) modified thus:

     (1)  The escape sequence `\n'  matches a newline embedded	in  the  buffer,
	  and `\t' matches a tab.

     (2)  A command line with no addresses selects every buffer.

     (3)  A  command  line  with  one address selects every buffer that  matches
	  that address.

     (4)  A command line with two addresses selects the inclusive range from the
	  first input buffer  that matches the first address  through  the  next
	  input  buffer   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.) Once the second address is matched sed starts look-
	  ing for the first one again; thus,  any number of these ranges will be
	  matched.

     The negation operator '!' can prefix a command to apply it  to  every  line
     not selected by the address(es).

     In the following list of functions, the maximum number of addresses permit-
     ted for each function is indicated in parentheses.

     An argument denoted "text" consists of one or more lines,	with all but the
     last ending with `' to hide the newline.

     Backslashes  in text are treated like backslashes in the replacement string
     of an `s' command and may be used to protect initial whitespace (blanks and
     tabs) against the stripping that is done on every line  of the script.

     An argument denoted "rfile" or "wfile"  must be last on the  command  line.
     Each  wfile  is  created before processing begins.  There can be at most 10
     distinct wfile arguments.

     a "text"	(1)
	  Append. Place text on output before reading the next input line.

     b "label"	(2)
	  Branch to the `:' command bearing the label.	If no label  is   given,
	  branch to the end of the script.

     c "text"	(2)
	  Change.  Delete  the current text buffer.  With 0 or 1 address,  or at
	  the end of a 2-address range, place text on  the  output.   Start  the
	  next cycle.

     d		(2)
	  Delete the current text buffer. Start the next cycle.

     D		(2)
	  Delete  the first line of the current text buffer (all chars up to the
	  first newline). Start the next cycle.

     g		(2)
	  Replace the contents of the current text buffer with the contents   of
	  the hold space.

     G		(2)
	  Append the contents of the hold space to the current text buffer.

     h		(2)
	  Copy the current text buffer into the hold space.

     H		(2)
	  Append a copy of the current text buffer to the hold space.

     i "text"	(1)
	  Insert. Place text on the standard output.

     l		(2)
	  List.  Sends	the  pattern space to standard output.	A "w" option may
	  follow as in the s command below. Non-printable characters expand to:

	     \b  --  backspace (ASCII 08)
	     \t  --  tab       (ASCII 09)
	     \n  --  newline   (ASCII 10)
	     \r  --  return    (ASCII 13)
	     \e  --  escape    (ASCII 27)
	     \xx --  the ASCII character corresponding to 2 hex digits xx.

     Dump.  Hex-dump the pattern space to standard output.

     n		(2)
	  Copy the current text buffer to standard output. Read the next line of
	  input into it.

     N		(2)
	  Append the next line of input to the current text buffer, inserting an
	  embedded newline between the two. The current line number changes.

     p		(2)
	  Print. Copy the current text buffer to the standard output.

     P		(2)
	  Copy the first line of the current text buffer (all chars  up  to  the
	  first newline) to standard output.

     q		(1)
	  Quit. Branch to the end of the script. Do not start a new cycle.

     r "rfile"	(1)
	  Read	the  contents  of rfile. Place them on the output before reading
	  the next input line.

     s /regular expression/replacement/flags	     (2)
	  Substitute the replacement for instances of the regular  expression in
	  the current text buffer.  Any character may be used  instead	of  `/'.
	  For  a  fuller  description  see ed (1).  Flags is zero or more of the
	  following:

	  g -- Global. Substitute for all nonoverlapping instances of the string
	       rather than just the first one.

	  p -- Print the pattern space if a replacement was made.

	  w -- Write. Append the current text buffer to a file argument as in  a
	       w command if a replacement is made. Standard output is used if no
	       file argument is given

     t "label"	(2)
	  Branch-if-test. Branch to the : command with the given  label  if  any
	  substitutes have been made since the most recent read of an input line
	  or execution of a `t'or `T'.	If no label is given,  branch to the end
	  of the script.

     T "label"	(2)
	  Branch-on-error.  Branch  to the : command with the given label if  no
	  substitutes have succeeded since the last input line or t  or  T  com-
	  mand.  Branch to the end of the script if no label is given.

     w "wfile"	(2)
	  Write. Append the current text buffer to wfile .

     W "wfile"	(2)
	  Write  first	line.	Append first line  of the current text buffer to
	  wfile.

     x		(2)
	  Exchange the contents of the current text buffer and hold space.

     y /string1/string2/      (2)
	  Translate. Replace each occurrence of a character   in  string1   with
	  the corresponding character in string2.  The lengths of  these strings
	  must be equal.

     ! "command"	      (2)
	  All-but.   Apply  the  function (or group, if function is `{') only to
	  lines not selected by the address(es).

     : "label"	(0)
	  This command does nothing but hold a label for `b' and `t' commands to
	  branch to.

     =		(1)
	  Place the current line number on the standard output as a line.

     {		(2)
	  Execute the following commands through a matching `}'  only  when  the
	  current line matches the address or address range given.

     An empty command is ignored.

PORTABILITY
     This  tool was reverse-engineered from BSD 4.1 UNIX sed, and (as far as the
     author's knowledge and tests can determine) is  compatible   with	it.  All
     documented features of BSD 4.1 sed are supported.

     One  undocumented	feature  (a  leading 'n' in the first comment having the
     same effect as an	-n command-line option)  has been omitted.

     The following bugs and limitations have been fixed:

     *	  There is no hidden length limit (40 in BSD sed) on w file names.

     *	  There is no limit (8 in BSD sed) on the length of labels.

     *	  The exchange command now works for long pattern and hold spaces.

     The following enhancements to existing commands have been made:

     *	  a, i commands don't insist on a leading backslash-\n in the text.

     *	  r, w commands don't insist on whitespace before the filename.

     *	  The g, p and P options on s commands may be given in any order.

     Some enhancements to regular-expression syntax have been made:

     *	  \t is recognized in REs (and elswhere) as an escape for tab.

     *	  In an RE, + calls for 1..n repeats of the previous pattern.

     The following are completely new features:

     *	  The l command (list, undocumented and weaker in BSD)

     The 'L' command (hex dump).

     *	  The W command (write first line of pattern space to file).

     *	  The T command (branch on last substitute failed).

     *	  Trailing comments are now allowed on command lines.

     In addition,  sed's error messages have been made more specific and  infor-
     mative.

     The implementation is also  significantly	smaller and  faster than BSD 4.1
     sed. It uses only the standard I/O library and exit(3).

SEE ALSO
     ed(1), grep(1), awk(1), lex(1), regexp(5)

AUTHOR
     Eric  S. Raymond <esr@snark.thyrsus.com> and Rene Rebe <rene@exactcode.de>.
     This program is distributed under a BSD-like license.

				October 15, 2021			  sed(1)
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