From Linux Man Pages
sed - stream editor for filtering and transforming text
sed [OPTION]... {script-only-if-no-other-script} [input-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.
-n, --quiet, --silent
suppress automatic printing of pattern space
-e script, --expression=script
add the script to the commands to be executed
-f script-file, --file=script-file
add the contents of script-file to the commands to be executed
-i[SUFFIX], --in-place[=SUFFIX]
edit files in place (makes backup if extension supplied)
-l N, --line-length=N
specify the desired line-wrap length for the `l' command
--posix
disable all GNU extensions.
-r, --regexp-extended
use extended regular expressions in the script.
-s, --separate
consider files as separate rather than as a single continuous long stream.
-u, --unbuffered
load minimal amounts of data from the input files and flush the output buffers more often
--help display this help and exit
--version
output version information and exit
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.
E-mail bug reports to: bonzini@gnu.org . Be sure to include the word ``sed somewhere in the ``Subject:
field.
COMMAND SYNOPSIS
This is just a brief synopsis of sed commands to serve as a reminder to those who already know sed; other docu-
mentation (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 preceded by a backslash.
i \
text Insert text, which has each embedded newline preceded by a backslash.
q Immediately quit the sed script without processing any more input, except that if auto-print is not dis-
abled the current pattern space will be printed.
Q Immediately quit the sed script without processing any more input.
r filename
Append text read from filename.
R filename
Append a line 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 or T
command, then branch to label; if label is omitted, branch to end of script.
T label
If no s/// has done a successful substitution since the last input line was read and since the last t or 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 preceded 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.
W filename
Write the first line of 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 com-
mand 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 an extension.)
$ Match the last line.
/regexp/
Match lines matching the regular expression regexp.
\cregexpc
Match lines matching the regular expression regexp. The c may be any character.
GNU sed also supports some special 2-address forms:
0,addr2
Start out in "matched first address" state, until addr2 is found. This is similar to 1,addr2, except that
if addr2 matches the very first line of input the 0,addr2 form will be at the end of its range, whereas
the 1,addr2 form will still be at the beginning of its range.
addr1,+N
Will match addr1 and the N lines following addr1.
addr1,~N
Will match addr1 and the lines following addr1 until the next line whose input line number is a multiple
of N.
REGULAR EXPRESSIONS
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.
BUGS
E-mail bug reports to bonzini@gnu.org. Be sure to include the word ``sed somewhere in the ``Subject: field.
Also, please include the output of ``sed --version in the body of your report if at all possible.
COPYRIGHT
Copyright � 2003 Free Software Foundation, Inc.
This is free software; see the source for copying conditions. There is NO warranty; not even for MERCHANTABILITY
or FITNESS FOR A PARTICULAR PURPOSE, to the extent permitted by law.
RELATED
awk(1), ed(1), grep(1), tr(1), perlre(1), sed.info, any of various books on sed, the sed FAQ
(http://sed.sf.net/grabbag/tutorials/sedfaq.txt), http://sed.sf.net/grabbag/.
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
info sed
should give you access to the complete manual.
CATEGORY