SED

SED(1)                          User Commands                         SED(1)

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

–follow-symlinks

follow symlinks when processing in place

-i[SUFFIX], –in-place[=SUFFIX]

edit files in place (makes backup if SUFFIX 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

-z, –null-data

separate lines by NUL characters

–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.

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 protected]>.  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 [exit-code]
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.  The exit code argument is a
GNU extension.

Q [exit-code]
Immediately quit the sed script without processing any more
input.  This is a GNU extension.

r filename
Append text read from filename.

R filename
Append a line read from filename.  Each invocation of the
command reads a line from the file.  This is a GNU extension.

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.

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      If pattern space contains no newline, start a normal new cycle
as if the d command was issued.  Otherwise, delete text in the
pattern space up to the first newline, and restart cycle with
the resultant pattern space, without reading a new line of
input.

h H    Copy/append pattern space to hold space.

g G    Copy/append hold space to pattern space.

l      List out the current line in a “visually unambiguous” form.

l width
List out the current line in a “visually unambiguous” form,
breaking it at width characters.  This is a GNU extension.

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.

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.
This is a GNU extension.

w filename
Write the current pattern space to filename.

W filename
Write the first line of the current pattern space to filename.
This is a GNU extension.

x      Exchange the contents of the hold and pattern spaces.

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 (which increments
cumulatively across files, unless the -s option is specified
on the command line).

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.  first can be zero; in
this case, sed operates as if it were equal to step.  (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.  This works only when addr2
is a regular expression.

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 [email protected].  Also, please include the
output of “sed –version” in the body of your report if at all
possible.

AUTHOR

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 protected]>.  Be sure to include the word “sed”
somewhere in the “Subject:” field.

COPYRIGHT

Copyright © 2012 Free Software Foundation, Inc.  License GPLv3+: GNU
GPL version 3 or later <http://gnu.org/licenses/gpl.html>.
This is free software: you are free to change and redistribute it.
There is NO WARRANTY, 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.

COLOPHON

This page is part of the sed (stream-oriented editor) project.
Information about the project can be found at
⟨http://www.gnu.org/software/sed/⟩.  If you have a bug report for this
manual page, send it to [email protected].  This page was obtained from
the tarball sed-4.2.2.tar.gz fetched from
⟨https://www.gnu.org/software/sed/⟩ on 2014-12-30.  If you discover
any rendering problems in this HTML version of the page, or you
believe there is a better or more up-to-date source for the page, or
you have corrections or improvements to the information in this
COLOPHON (which is not part of the original manual page), send a mail
to [email protected]

sed 4.2.2                       December 2012                         SED(1)