sed: Command-Line Options
2.2 Command-Line Options
========================
The full format for invoking 'sed' is:
sed OPTIONS... [SCRIPT] [INPUTFILE...]
'sed' may be invoked with the following command-line options:
'--version'
Print out the version of 'sed' that is being run and a copyright
notice, then exit.
'--help'
Print a usage message briefly summarizing these command-line
options and the bug-reporting address, then exit.
'-n'
'--quiet'
'--silent'
By default, 'sed' prints out the pattern space at the end of each
cycle through the script (⇒How 'sed' works Execution Cycle.).
These options disable this automatic printing, and 'sed' only
produces output when explicitly told to via the 'p' command.
'--debug'
Print the input sed program in canonical form, and annotate program
execution.
$ echo 1 | sed '\%1%s21232'
3
$ echo 1 | sed --debug '\%1%s21232'
SED PROGRAM:
/1/ s/1/3/
INPUT: 'STDIN' line 1
PATTERN: 1
COMMAND: /1/ s/1/3/
PATTERN: 3
END-OF-CYCLE:
3
'-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.
'-i[SUFFIX]'
'--in-place[=SUFFIX]'
This option specifies that files are to be edited in-place. GNU
'sed' does this by creating a temporary file and sending output to
this file rather than to the standard output.(1).
This option implies '-s'.
When the end of the file is reached, the temporary file is renamed
to the output file's original name. The extension, if supplied, is
used to modify the name of the old file before renaming the
temporary file, thereby making a backup copy(2)).
This rule is followed: if the extension doesn't contain a '*', then
it is appended to the end of the current filename as a suffix; if
the extension does contain one or more '*' characters, then _each_
asterisk is replaced with the current filename. This allows you to
add a prefix to the backup file, instead of (or in addition to) a
suffix, or even to place backup copies of the original files into
another directory (provided the directory already exists).
If no extension is supplied, the original file is overwritten
without making a backup.
Because '-i' takes an optional argument, it should not be followed
by other short options:
'sed -Ei '...' FILE'
Same as '-E -i' with no backup suffix - 'FILE' will be edited
in-place without creating a backup.
'sed -iE '...' FILE'
This is equivalent to '--in-place=E', creating 'FILEE' as
backup of 'FILE'
Be cautious of using '-n' with '-i': the former disables automatic
printing of lines and the latter changes the file in-place without
a backup. Used carelessly (and without an explicit 'p' command),
the output file will be empty:
# WRONG USAGE: 'FILE' will be truncated.
sed -ni 's/foo/bar/' FILE
'-l N'
'--line-length=N'
Specify the default line-wrap length for the 'l' command. A length
of 0 (zero) means to never wrap long lines. If not specified, it
is taken to be 70.
'--posix'
GNU 'sed' includes several extensions to POSIX sed. In order to
simplify writing portable scripts, this option disables all the
extensions that this manual documents, including additional
commands. Most of the extensions accept 'sed' programs that are
outside the syntax mandated by POSIX, but some of them (such as the
behavior of the 'N' command described in ⇒Reporting Bugs)
actually violate the standard. If you want to disable only the
latter kind of extension, you can set the 'POSIXLY_CORRECT'
variable to a non-empty value.
'-b'
'--binary'
This option is available on every platform, but is only effective
where the operating system makes a distinction between text files
and binary files. When such a distinction is made--as is the case
for MS-DOS, Windows, Cygwin--text files are composed of lines
separated by a carriage return _and_ a line feed character, and
'sed' does not see the ending CR. When this option is specified,
'sed' will open input files in binary mode, thus not requesting
this special processing and considering lines to end at a line
feed.
'--follow-symlinks'
This option is available only on platforms that support symbolic
links and has an effect only if option '-i' is specified. In this
case, if the file that is specified on the command line is a
symbolic link, 'sed' will follow the link and edit the ultimate
destination of the link. The default behavior is to break the
symbolic link, so that the link destination will not be modified.
'-E'
'-r'
'--regexp-extended'
Use extended regular expressions rather than basic regular
expressions. Extended regexps are those that 'egrep' accepts; they
can be clearer because they usually have fewer backslashes.
Historically this was a GNU extension, but the '-E' extension has
since been added to the POSIX standard
(http://austingroupbugs.net/view.php?id=528), so use '-E' for
portability. GNU sed has accepted '-E' as an undocumented option
for years, and *BSD seds have accepted '-E' for years as well, but
scripts that use '-E' might not port to other older systems. ⇒
Extended regular expressions ERE syntax.
'-s'
'--separate'
By default, 'sed' will consider the files specified on the command
line as a single continuous long stream. This GNU 'sed' extension
allows the user to consider them as separate files: range addresses
(such as '/abc/,/def/') are not allowed to span several files, line
numbers are relative to the start of each file, '$' refers to the
last line of each file, and files invoked from the 'R' commands are
rewound at the start of each file.
'--sandbox'
In sandbox mode, 'e/w/r' commands are rejected - programs
containing them will be aborted without being run. Sandbox mode
ensures 'sed' operates only on the input files designated on the
command line, and cannot run external programs.
'-u'
'--unbuffered'
Buffer both input and output as minimally as practical. (This is
particularly useful if the input is coming from the likes of 'tail
-f', and you wish to see the transformed output as soon as
possible.)
'-z'
'--null-data'
'--zero-terminated'
Treat the input as a set of lines, each terminated by a zero byte
(the ASCII 'NUL' character) instead of a newline. This option can
be used with commands like 'sort -z' and 'find -print0' to process
arbitrary file names.
If no '-e', '-f', '--expression', or '--file' options are given on
the command-line, 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 be processed if no file names are specified.
---------- Footnotes ----------
(1) This applies to commands such as '=', 'a', 'c', 'i', 'l', 'p'.
You can still write to the standard output by using the 'w' or 'W'
commands together with the '/dev/stdout' special file
(2) Note that GNU 'sed' creates the backup file whether or not any
output is actually changed.
Info Catalog
sed: Overview
sed: Invoking sed
sed: Exit status