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SED
!!!SED
NAME
SYNOPSIS
DESCRIPTION
OPTIONS
Command Synopsis
Addresses
Regular expressions
Miscellaneous notes
SEE ALSO
BUGS
----
!!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
perform 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
processed 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
documentation (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
preceeded by a backslash.


i \


''text''


Insert ''text'', which has each embedded newline
preceeded 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 pattern
space. Start next cycle, but skip reading from the input if
there is still data in the pattern 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 unambiguous''
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 current
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
special 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
''filename''.


y/''source''/''dest''/


Transliterate the characters in the pattern space which
appear in ''source'' to the corresponding character 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 second
address. Three things to note about address ranges: the
syntax is ''addr1'',''addr2'' (i.e., the addresses are
separated 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
command, a __!__ may be inserted, which specifies that
the command 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''.


\__c__''regexp''__c__


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
completely 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 \____
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(7) [[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.
----
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Last edited on Tuesday, June 4, 2002 12:22:51 am by "perry"
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