sed(1)
NAME
sed - stream editor
SYNOPSIS
/usr/bin/sed [-n] script [file...]
/usr/bin/sed [-n] [-e script]... [-f script_file]...
[file...]
/usr/xpg4/bin/sed [-n] script [file...]
/usr/xpg4/bin/sed [-n] [-e script]... [-f script_file]...
[file...]
DESCRIPTION
The sed utility is a stream editor that reads one or more
text files, makes editing changes according to a script of
editing commands, and writes the results to standard output.
The script is obtained from either the script operand
string, or a combination of the option-arguments from the -e
script and -f script_file options.
The sed utility is a text editor. It cannot edit binary
files or files containing ASCII NUL (\0) characters or very
long lines.
OPTIONS
The following options are supported:
-e script
script is an edit command for sed. See USAGE below for
more information on the format of script. If there is
just one -e option and no -f options, the flag -e may
be omitted.
-f script_file
Takes the script from script_file. script_file con-
sists of editing commands, one per line.
-n Suppresses the default output.
Multiple -e and -f options may be specified. All commands
are added to the script in the order specified, regardless
of their origin.
OPERANDS
The following operands are supported:
file A path name of a file whose contents will be read and
edited. If multiple file operands are specified, the
named files will be read in the order specified and
the concatenation will be edited. If no file operands
are specified, the standard input will be used.
script
A string to be used as the script of editing commands.
The application must not present a script that
violates the restrictions of a text file except that
the final character need not be a NEWLINE character.
USAGE
A script consists of editing commands, one per line, of the
following form:
[ address [ , address ] ] command [ arguments ]
Zero or more blank characters are accepted before the first
address and before command. Any number of semicolons are
accepted before the first address.
In normal operation, sed cyclically copies a line of input
(less its terminating NEWLINE character) into a pattern
space (unless there is something left after a D command),
applies in sequence all commands whose addresses select that
pattern space, and copies the resulting pattern space to the
standard output (except under -n) and deletes the pattern
space. Whenever the pattern space is written to standard
output or a named file, sed will immediately follow it with
a NEWLINE character.
Some of the commands use a hold space to save all or part
of the pattern space for subsequent retrieval. The pattern
and hold spaces will each be able to hold at least 8192
bytes.
sed Addresses
An address is either empty, a decimal number that counts
input lines cumulatively across files, a $ that addresses
the last line of input, or a context address, which consists
of a /regular expression/ as described on the regexp(5)
manual page.
A command line with no addresses selects every pattern
space.
A command line with one address selects each pattern space
that matches the address.
A command line with two addresses selects the inclusive
range from the first pattern space that matches the first
address through the next pattern space that matches the
second address. Thereafter the process is repeated, looking
again for the first address. (If the second address is a
number less than or equal to the line number selected by the
first address, only the line corresponding to the first
address is selected.)
Typically, address are separated from each other by a comma
(,). They may also be separated by a semicolon (;).
sed Regular Expressions
sed supports the basic regular expressions described on the
regexp(5) manual page, with the following additions:
\cREc In a context address, the construction \cREc, where c
is any character other than a backslash or NEWLINE
character, is identical to /RE/. If the character
designated by c appears following a backslash, then it
is considered to be that literal character, which does
not terminate the RE. For example, in the context
address \xabc\xdefx, the second x stands for itself,
so that the regular expression is abcxdef.
\n The escape sequence \n matches a NEWLINE character
embedded in the pattern space. A literal NEWLINE
character must not be used in the regular expression
of a context address or in the substitute command.
Editing commands can be applied only to non-selected pattern
spaces by use of the negation command ! (described below).
sed Editing Commands
In the following list of functions the maximum number of
permissible addresses for each function is indicated.
The r and w commands take an optional rfile (or wfile)
parameter, separated from the command letter by one or more
blank characters.
Multiple commands can be specified by separating them with a
semicolon (;) on the same command line.
The text argument consists of one or more lines, all but the
last of which end with \ to hide the NEWLINE. Each embedded
NEWLINE character in the text must be preceded by a
backslash. Other backslashes in text are removed and the
following character is treated literally. Backslashes in
text are treated like backslashes in the replacement string
of an s command, and may be used to protect initial blanks
and tabs against the stripping that is done on every script
line. The rfile or wfile argument must terminate the com-
mand line and must be preceded by exactly one blank. The
use of the wfile parameter causes that file to be initially
created, if it does not exist, or will replace the contents
of an existing file. There can be at most 10 distinct wfile
arguments.
Regular expressions match entire strings, not just indivi-
dual lines, but a NEWLINE character is matched by \n in a
sed RE. A NEWLINE character is not allowed in an RE. Also
notice that \n cannot be used to match a NEWLINE character
at the end of an input line; NEWLINE characters appear in
the pattern space as a result of the N editing command.
Two of the commands take a command-list, which is a list of
sed commands separated by NEWLINE characters, as follows:
{ command
command
}
The { can be preceded with blank characters and can be fol-
lowed with white space. The commands can be preceded by
white space. The terminating } must be preceded by a NEWLINE
character and can be preceded or followed by <blank>s. The
braces may be preceded or followed by <blank>s. The command
may be preceded by <blank>s, but may not be followed by
<blank>s.
The following table lists the functions, with the maximum
number of permissible addresses.
_________________________________________________________________
Max Address Command Description
_________________________________________________________________
1 a\ text Append by executing N command or
beginning a new cycle. Place
text on the output before read-
ing the next input line.
_________________________________________________________________
2 b label Branch to the : command bearing
the label . If label is empty,
branch to the end of the script.
Labels are recognized unique up
to eight characters.
_________________________________________________________________
2 c\ text Change. Delete the pattern
space. Place text on the out-
put. Start the next cycle.
_________________________________________________________________
2 d Delete the pattern space. Start
the next cycle.
_________________________________________________________________
2 D Delete the initial segment of
the pattern space through the
first new-line. Start the next
cycle. (See the N command
below.)
_________________________________________________________________
2 g Replace the contents of the pat-
tern space by the contents of
the hold space.
_________________________________________________________________
2 G Append the contents of the hold
space to the pattern space.
_________________________________________________________________
2 h Replace the contents of the hold
space by the contents of the
pattern space.
_________________________________________________________________
2 H Append the contents of the pat-
tern space to the hold space.
_________________________________________________________________
1 i\ text Insert. Place text on the stan-
dard output.
_________________________________________________________________
2 l /usr/bin/sed: List the pattern
space on the standard output in
an unambiguous form. Non-
printable characters are
displayed in octal notation and
long lines are folded.
_________________________________________________________________
/usr/xpg4/bin/sed: List the
pattern space on the standard
output in an unambiguous form.
Non-printable characters are
displayed in octal notation and
long lines are folded. The char-
acters (\\, \a, \b, \f, \r, \t,
and \v) are written as the
corresponding escape sequences.
Non-printable characters not in
that table will be written as
one three-digit octal number
(with a preceding backslash
character) for each byte in the
character (most significant byte
first). If the size of a byte on
the system is greater than nine
bits, the format used for non-
printable characters is imple-
mentation dependent.
_________________________________________________________________
Long lines are folded, with the
point of folding indicated by
writing a backslash followed by
a NEWLINE; the length at which
folding occurs is unspecified,
but should be appropriate for
the output device. The end of
each line is marked with a $.
_________________________________________________________________
2 n Copy the pattern space to the
standard output if default out-
put is not suppressed. Replace
the pattern space with the next
line of input.
_________________________________________________________________
2 N Append the next line of input to
the pattern space with an embed-
ded new-line. (The current line
number changes.) If no next
line of input is available, the
N command verb shall branch to
the end of the script and quit
without starting a new cycle and
without writing the pattern
space.
_________________________________________________________________
2 p Print. Copy the pattern space
to the standard output.
_________________________________________________________________
2 P Copy the initial segment of the
pattern space through the first
new-line to the standard output.
_________________________________________________________________
1 q Quit. Branch to the end of the
script. Do not start a new
cycle.
_________________________________________________________________
2 r rfile Read the contents of rfile.
Place them on the output before
reading the next input line. If
rfile does not exist or cannot
be read, it is treated as if it
were an empty file, causing no
error condition.
_________________________________________________________________
2 t label Test. Branch to the : command
bearing the label if any substi-
tutions have been made since the
most recent reading of an input
line or execution of a t. If
label is empty, branch to the
end of the script.
_________________________________________________________________
2 w wfile Write. Append the pattern space
to wfile. The first occurrence
of w will cause wfile to be
cleared. Subsequent invocations
of w will append. Each time the
sed command is used, wfile is
overwritten.
_________________________________________________________________
2 x Exchange the contents of the
pattern and hold spaces.
_________________________________________________________________
2 ! command Don't. Apply the command (or
group, if command is {) only to
lines not selected by the
address(es).
_________________________________________________________________
0 : label This command does nothing; it
bears a label for b and t com-
mands to branch to.
_________________________________________________________________
1 = Place the current line number on
the standard output as a line.
_________________________________________________________________
2 {command-list} Execute command-list only when
the pattern space is selected.
_________________________________________________________________
0 An empty command is ignored.
_________________________________________________________________
| 0 | # | If a # appears as the first|
| | | character on a line of a script|
| | | file, then that entire line is|
| | | treated as a comment, with one|
| | | exception: if a # appears on the|
| | | first line and the character|
| | | after the # is an n, then the|
| | | default output will be|
| | | suppressed. The rest of the|
| | | line after #n is also ignored.|
| | | A script file must contain at|
| | | least one non-comment line. |
|____________|________________|__________________________________|
____________________________________________________________
Max Addr Command (Using strings) and Description
____________________________________________________________
2 s/regular expression/replacement/flags
____________________________________________________________
Substitute the replacement string for
instances of the regular expression in the
pattern space. Any character other than
backslash or newline can be used instead of a
slash to delimit the RE and the replacement.
Within the RE and the replacement, the RE del-
imiter itself can be used as a literal charac-
ter if it is preceded by a backslash.
____________________________________________________________
An ampersand (&) appearing in the replacement
will be replaced by the string matching the
RE. The special meaning of & in this context
can be suppressed by preceding it by
backslash. The characters \n, where n is a
digit, will be replaced by the text matched by
the corresponding backreference expression.
For each backslash (\) encountered in scanning
replacement from beginning to end, the follow-
ing character loses its special meaning (if
any). It is unspecified what special meaning
is given to any character other than &, \ or
digits.
____________________________________________________________
A line can be split by substituting a NEWLINE
character into it. The application must
escape the NEWLINE character in the replace-
ment by preceding it with backslash. A sub-
stitution is considered to have been performed
even if the replacement string is identical to
the string that it replaces.
____________________________________________________________
flags is zero or more of:
____________________________________________________________
n n= 1 - 512. Substitute for just the nth
occurrence of the regular expression.
____________________________________________________________
g Global. Substitute for all nonoverlapping
instances of the regular expression rather
than just the first one. If both g and n are
specified, the results are unspecified.
____________________________________________________________
p Print the pattern space if a replacement was
made.
____________________________________________________________
P Copy the initial segment of the pattern
space through the first new-line to the stan-
dard output.
____________________________________________________________
| | w wfile Write. Append the pattern space to|
| | wfile if a replacement was made. The first|
| | occurrence of w will cause wfile to be|
| | cleared. Subsequent invocations of w will|
| | append. Each time the sed command is used,|
| | wfile is overwritten. |
|___________|_______________________________________________|
| 2 | y/ string1 / |
|___________|_______________________________________________|
| string2 / | |
|___________|_______________________________________________|
| | Transform. Replace all occurrences of charac-|
| | ters in string1 with the corresponding char-|
| | acters in string2. string1 and string2 must|
| | have the same number of characters, or if any|
| | of the characters in string1 appear more than|
| | once, the results are undefined. Any charac-|
| | ter other than backslash or NEWLINE can be|
| | used instead of slash to delimit the strings.|
| | Within string1 and string2, the delimiter|
| | itself can be used as a literal character if|
| | it is preceded by a backslash. For example,|
| | y/abc/ABC/ replaces a with A, b with B, and c|
| | with C. |
|___________|_______________________________________________|
See largefile(5) for the description of the behavior of sed
when encountering files greater than or equal to 2 Gbyte ( 2
**31 bytes).
EXAMPLES
Example 1: An example sed script
This sed script simulates the BSD cat -s command, squeezing
excess blank lines from standard input.
sed -n '
# Write non-empty lines.
/./ {
p
d
}
# Write a single empty line, then look for more empty lines.
/^$/ p
# Get next line, discard the held <newline> (empty line),
# and look for more empty lines.
:Empty
/^$/ {
N
s/.//
b Empty
}
# Write the non-empty line before going back to search
# for the first in a set of empty lines.
p
'
ENVIRONMENT VARIABLES
See environ(5) for descriptions of the following environment
variables that affect the execution of sed: LANG, LC_ALL,
LC_COLLATE, LC_CTYPE, LC_MESSAGES, and NLSPATH.
EXIT STATUS
The following exit values are returned:
0 Successful completion.
>0 An error occurred.
ATTRIBUTES
See attributes(5) for descriptions of the following attri-
butes:
/usr/bin/sed
____________________________________________________________
| ATTRIBUTE TYPE | ATTRIBUTE VALUE |
|_____________________________|_____________________________|
| Availability | SUNWcsu |
|_____________________________|_____________________________|
| CSI | Not enabled |
|_____________________________|_____________________________|
/usr/xpg4/bin/sed
____________________________________________________________
| ATTRIBUTE TYPE | ATTRIBUTE VALUE |
|_____________________________|_____________________________|
| Availability | SUNWxcu4 |
|_____________________________|_____________________________|
| CSI | Enabled |
|_____________________________|_____________________________|
| Interface Stability | Standard |
|_____________________________|_____________________________|
SEE ALSO
awk(1), ed(1), grep(1), attributes(5), environ(5), large-
file(5), regexp(5), standards(5)
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