Section: User Commands (1)
Updated: December 2012
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.
If no -e, --expression, -f, or --file option is given, then the first non-option argument is taken as the sed script to interpret. All remaining arguments are names of input files; if no input files are specified, then the standard input is read.
GNU sed home page: <http://www.gnu.org/software/sed/>. General help using GNU software: <http://www.gnu.org/gethelp/>. E-mail bug reports to: <email@example.com>. Be sure to include the word ``sed somewhere in the ``Subject: field.
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:
GNU sed also supports some special 2-address forms:
POSIX.2 BREs should be supported, but they aren't completely because of performance problems. The \n sequence in a regular expression matches the newline character, and similarly for \a, \t, and other sequences.
E-mail bug reports to firstname.lastname@example.org. Also, please include the output of ``sed --version'' in the body of your report if at all possible.
Written by Jay Fenlason, Tom Lord, Ken Pizzini, and Paolo Bonzini. GNU sed home page: <http://www.gnu.org/software/sed/>. General help using GNU software: <http://www.gnu.org/gethelp/>. E-mail bug reports to: <email@example.com>. Be sure to include the word ``sed somewhere in the ``Subject: field.
Copyright © 2012 Free Software Foundation, Inc. License GPLv3+: GNU GPL version 3 or later <http://gnu.org/licenses/gpl.html>.
The full documentation for sed is maintained as a Texinfo manual. If the info and sed programs are properly installed at your site, the command
<DD CLASS="c3|info sed:
should give you access to the complete manual.
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