sed - Unix, Linux Command
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 seds ability to filter text in a pipeline
which particularly distinguishes it from other types of
editors.
Tag | Description |
-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.
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-r, --regexp-extended
|
|
use extended regular expressions in the script.
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-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
Tag | Description |
: 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
Tag | Description |
=
|
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
Tag | Description |
{
|
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:
Tag | Description |
number |
Match only the specified line
number. |
first~step | |
Match every
stepth 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 arent 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.
SEE ALSO
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
should give you access to the complete manual.
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