sed - a Stream EDitor
sed [-n] [-V] [--quiet] [--silent] [--version] [--help]
[-e script] [--expression=script]
[-f script-file] [--file=script-file]
[script-if-no-other-script]
[file...]
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.
Sed may be invoked with the following command-line options:
-V
--version
Print out the version of sed that is being run and a copyright
notice, then exit.
-h
--help Print a usage message briefly summarizing these command-line
options and the bug-reporting address, then exit.
-n
--quiet
--silent
By default, sed will print out the pattern space at the end of
each cycle through the script. These options disable this automatic
printing, and sed will only produce output when explicitly
told to via the p command.
-e script
--expression=script
Add the commands in script to the set of commands to be run
while processing the input.
-f script-file
--file=script-file
Add the commands contained in the file script-file to the set of
commands to be run while processing the input.
If no -e,-f,--expression, or --file options are given on the commandline,
then the first non-option argument on the command line is taken
to be the script to be executed.
If any command-line parameters remain after processing the above, these
parameters are interpreted as the names of input files to be processed.
A file name of - refers to the standard input stream. The standard
input will processed if no file names are specified.
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 [Toc] [Back]
= Print the current line number.
a \
text Append text, which has each embedded newline preceeded by a
backslash.
i \
text Insert text, which has each embedded newline preceeded by a
backslash.
q Immediately quit the sed script without processing any more
input, except that if auto-print is not diabled the current pattern
space will be printed.
r filename
Append text read from filename.
Commands which accept address ranges [Toc] [Back]
{ 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 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 preceeded 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.
y/source/dest/
Transliterate the characters in the pattern space which appear
in source to the corresponding character in dest.
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 a GNU 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.
POSIX.2 BREs should be supported, but they aren't completely yet. The
\n sequence in a regular expression matches the newline character.
There are also some GNU extensions. [XXX FIXME: more needs to be said.
At the very least, a reference to another document which describes what
is supported should be given.]
This version of sed supports a \<newline> sequence in all regular
expressions, the replacement part of a substitute (s) command, and in
the source and dest parts of a transliterate (y) command. The \ is
stripped, and the newline is kept.
awk(1), ed(1), expr(1), emacs(1), perl(1), tr(1), vi(1), regex(7)
[well, one ought to be written... XXX], sed.info, any of various books
on sed, the sed FAQ (http://www.wollery.demon.co.uk/sedtut10.txt,
http://www.ptug.org/sed/sedfaq.htm).
E-mail bug reports to bug-gnu-utils@gnu.org. Be sure to include the
word ``sed'' somewhere in the ``Subject:'' field.
GNU Project 1998-05-07 SED(1)
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