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SED(1)			  BSD General Commands Manual			SED(1)

     sed -- stream editor

     sed [-Ealn] command [file ...]
     sed [-Ealn] [-e command] [-f command_file]	[-i extension] [file ...]

     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.  Multiple
     commands may be specified by using	the -e or -f options.  All commands
     are applied to the	input in the order they	are specified regardless of
     their origin.

     The following options are available:

     -E	     Interpret regular expressions as extended (modern)	regular	ex-
	     pressions rather than basic regular expressions (BRE's).  The
	     re_format(7) manual page fully describes both formats.

     -a	     The files listed as parameters for	the "w"	functions are created
	     (or truncated) before any processing begins, by default.  The -a
	     option causes sed to delay	opening	each file until	a command con-
	     taining 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.

     -i	extension
	     Edit files	in-place, saving backups with the specified extension.
	     If	a zero-length extension	is given, no backup will be saved.  It
	     is	not recommended	to give	a zero-length extension	when in-place
	     editing files, as you risk	corruption or partial content in situ-
	     ations where disk space is	exhausted, etc.

     -l	     Make output line buffered.

     -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:


     Whitespace	may be inserted	before the first address and the function por-
     tions of the command.

     Normally, sed cyclically copies a line of input, not including its	termi-
     nating newline character, into a pattern space, (unless there is some-
     thing left	after a	"D" function), applies all of the commands with	ad-
     dresses 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 pattern
     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 an inclusive range.  This range
     starts with the first pattern space that matches the first	address.  The
     end of the	range is the next following pattern space that matches the
     second address.  If the second address is a number	less than or equal to
     the line number first selected, only that line is selected.  In the case
     when the second address is	a context address, sed does not	re-match the
     second address against the	pattern	space that matched the first address.
     Starting at the first line	following the selected range, sed starts look-
     ing 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 regular expressions used in sed, by default, are basic	regular	ex-
     pressions (BREs, see re_format(7) for more	information), but extended
     (modern) regular expressions can be used instead if the -E	flag is	given.
     In	addition, sed has the following	two additions to regular expressions:

     1.	  In a context address,	any character other than a backslash ("\") or
	  newline character may	be used	to delimit the regular expression.
	  Also,	putting	a backslash character before the delimiting character
	  causes the character to be treated literally.	 For example, in the
	  context address \xabc\xdefx, the RE delimiter	is an "x" and the sec-
	  ond "x" stands for itself, so	that the regular expression is

     2.	  The escape sequence \n matches a newline character embedded in the
	  pattern space.  You cannot, 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 ex-
     pression encountered is used instead.  The	last regular expression	is de-
     fined as the last regular expression used as part of an address or	sub-
     stitute 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 ad-
     dresses 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 in-
     put processing begins.

     The "b", "r", "s",	"t", "w", "y", "!", and	":" functions all accept addi-
     tional arguments.	The following synopses indicate	which arguments	have
     to	be separated 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:

	   { 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.

     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.

	     Branch to the ":" function	with the specified label.  If the la-
	     bel is not	specified, branch to the end of	the script.

     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.

	     Delete the	pattern	space and start	the next cycle.

	     Delete the	initial	segment	of the pattern space through the first
	     newline character and start the next cycle.

	     Replace the contents of the pattern space with the	contents of
	     the hold space.

	     Append a newline character	followed by the	contents of the	hold
	     space to the pattern space.

	     Replace the contents of the hold space with the contents of the
	     pattern space.

	     Append a newline character	followed by the	contents of the	pat-
	     tern space	to the hold space.

     text    Write text	to the standard	output.

	     (The letter ell.)	Write the pattern space	to the standard	output
	     in	a visually unambiguous form.  This form	is as follows:

		   backslash	      \\
		   alert	      \a
		   form-feed	      \f
		   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	indicated by displaying	a backslash followed by	a new-
	     line.  The	end of each line is marked with	a "$".

	     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.

	     Append the	next line of input to the pattern space, using an em-
	     bedded newline character to separate the appended material	from
	     the original contents.  Note that the current line	number

	     Write the pattern space to	standard output.

	     Write the pattern space, up to the	first newline character	to the
	     standard output.

	     Branch to the end of the script and quit without starting a new

     [1addr]r file
	     Copy the contents of file to the standard output immediately be-
	     fore the next attempt to read a line of input.  If	file cannot be
	     read for any reason, it is	silently ignored and no	error condi-
	     tion 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 de-
	     limit the RE and the replacement.	Within the RE and the replace-
	     ment, 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 "\#", where	"#" is a digit,	is replaced by the text
	     matched by	the corresponding backreference	expression (see

	     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:

		   N	   Make	the substitution only for the N'th occurrence
			   of the regular expression in	the pattern space.

		   g	   Make	the substitution for all non-overlapping
			   matches of the regular expression, not just the
			   first one.

		   p	   Write the pattern space to standard output if a re-
			   placement was made.	If the replacement string is
			   identical to	that which it replaces,	it is still
			   considered to have been a replacement.

		   w file  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.

	     Swap the contents of the pattern and hold spaces.

	     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	re-
	     placed by a newline character.

	     Apply the function	or function-list only to the lines that	are
	     not selected by the address(es).

	     This function does	nothing; it bears a label to which the "b" and
	     "t" commands may branch.

	     Write the line number to the standard output followed by a	new-
	     line character.

	     Empty lines are ignored.

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

     The COLUMNS, LANG,	LC_ALL,	LC_CTYPE and LC_COLLATE	environment variables
     affect the	execution of sed as described in environ(7).

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

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

     The sed utility is	expected to be a superset of the IEEE Std 1003.2
     ("POSIX.2") specification.

     The -E, -a	and -i options are non-standard	FreeBSD	extensions and may not
     be	available on other operating systems.

     A sed command, written by L. E. McMahon, appeared in Version 7 AT&T UNIX.

     Diomidis D. Spinellis <>

     Multibyte characters containing a byte with value 0x5C (ASCII `\')	may be
     incorrectly treated as line continuation characters in arguments to the
     "a", "c" and "i" commands.	 Multibyte characters cannot be	used as	delim-
     iters with	the "s"	and "y"	commands.

BSD				 May 10, 2005				   BSD


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