SED(1) User Commands December 2010

sed - stream editor for filtering and transforming text

NAME

sed - stream editor for filtering and transforming text

SYNOPSIS

sed

[OPTION]... {script-only-if-no-other-script} [input-file]...

DESCRIPTION

.ds sd \fIsed\fP

.ds Sd \fISed\fP

*(Sd 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), *(sd works by making only one pass over the input(s), and is consequently more efficient. But it is *(sd's ability to filter text in a pipeline which particularly distinguishes it from other types of editors.

.HP

-n, --quiet, --silent
--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 *(sd commands to serve as a reminder to those who already know *(sd; other documentation (such as the texinfo document) must be consulted for fuller descriptions.

.SS

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.

.SS

Zero- or One- address commands
=
Print the current line number.
a e
text
Append

text,

which has each embedded newline preceded by a backslash.
i e
text
Insert

text,

which has each embedded newline preceded by a backslash.
q [exit-code]
Immediately quit the *(sd 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 *(sd 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.

.SS

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 e
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.
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 e1 through e9 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.

.SH

Addresses *(Sd 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.

first

can be zero; in this case, *(sd operates as if it were equal to

step.

(This is an extension.)
$
Match the last line.
/regexp /
Match lines matching the regular expression

regexp.

ecregexpc
Match lines matching the regular expression

regexp.

The

c

may be any character.

GNU *(sd 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

en

sequence in a regular expression matches the newline character, and similarly for

ea,

et,

and other sequences.

BUGS

E-mail bug reports to

[email protected].

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.

SEE ALSO

awk(1),

ed(1),

grep(1),

tr(1),

perlre(1),

sed.info, any of various books on *(sd,

.na

the *(sd 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.