NAME
sed - stream editor for filtering and transforming
text
SYNOPSIS
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)
- -c, --copy
- use copy instead of rename when shuffling files in -i
mode (avoids change of input file ownership)
- -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 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 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 disabled 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 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 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 . 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.
SEE ALSO
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.