SED(1) SED(1)
sed - stream editor
sed [-n] script [file ...]
sed [-n] [-e script]... [-f script_file]... [file ...]
sed copies the named files (standard input default) to the standard
output, edited according to a script of commands. The -e option causes
the script to be take from the script option argument. The -f option
causes the script to be taken from file script_file. The scripts from
the -e and -f options accumulate. If there is just one -e option and no
-f options, the flag -e may be omitted. The -n option suppresses the
default output.
sed has two operating modes. By default, sed operates compatibly with
certain earlier versions of System V sed. If the environment variable
_XPG is defined, and has a numeric value greater than 0, sed operates in
conformance with the X/Open XPG4 specifications. In the backward
compatibility mode, when -n is not specified and the "p" option to the
"s" command is used, the pattern space will be output only once, no
matter how many substitutions are made. Also, the format of the output
of the "l" command will differ in some details from the XPG4 format.
Note that the null string is a part of the solutions when _XPG numerical
value > 0. i.e., sed -e 's/b*/a/' will insert "a" at the beginning of any
input as "b*" would match an empty string. To substitute the first nonempty
string consisting of one or more letter b's with "a", then it
should be: sed -e 's/bb*/a/'
A script consists of editing commands, one per line, of the following
form:
[ address [ , address ] ] function [ arguments ]
Zero or more blank characters are accepted before the first address and
before command.
Each input file is a text file to be edited. The files are read in the
order given.
In normal operation, sed cyclically copies a line of input 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 at
the end of the script copies the pattern space to the standard output
(except when -n is specified) 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.
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SED(1) SED(1)
Some of the commands use a hold space to save all or part of the pattern
space for subsequent retrieval. The hold and pattern spaces each hold at
least 8192 bytes.
An address is either a decimal number that counts input lines
cumulatively across files, a $ that addresses the last line of input, or
a context address, i.e., a /regular expression/ in the style of ed(1)
modified thus:
In a context address, the construction \?regular expression?, where
? is any character, is identical to /regular expression/.
Note that in the context address \xabc\xdefx, the second x
stands for itself, so that the regular expression is abcxdef.
The escape sequence \n matches a new-line embedded in the pattern
space.
A period . matches any character except the terminal new-line of the
pattern space.
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. (If the second
address is a number less than or equal to the line number first
selected, only one line is selected.) Thereafter the process
is repeated, looking again for the first address.
\< and \> are not currently supported.
Editing commands can be applied only to non-selected pattern spaces by
use of the negation function ! (below).
In the following list of functions the maximum number of permissible
addresses for each function is indicated in parentheses.
The text argument consists of one or more lines, all but the last of
which end with \ to hide the new-line. 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 command line and must be preceded by exactly one blank. Each wfile
is created before processing begins. There can be at most 10 distinct
wfile arguments.
(1)a\
text Append. Place text on the output before reading 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.
(2)c\
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SED(1) SED(1)
text Change. Delete the pattern space. With 0 or 1 address or at
the end of a 2-address range, place text on the output. 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.
(2)g Replace the contents of the pattern 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 pattern space to the hold space.
(1)i\
text Insert. Place text on the standard output.
(2)l 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.
(2)n Copy the pattern space to the standard output. Replace the
pattern space with the next line of input.
(2)N Append the next line of input to the pattern space with an
embedded new-line. (The current line number changes.)
(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.
(2)s/regular expression/replacement/flags
Substitute the replacement string for instances of the regular
expression in the pattern space. Any character may be used
instead of /. For a fuller description see ed(1). Flags is
zero or more of:
n n= 1 - 512. Substitute for just the n th occurrence
of the regular expression.
g Global. Substitute for all nonoverlapping instances
of the regular expression rather than just the first
one.
p Print the pattern space if a replacement was made.
w wfile Write. Append the pattern space to wfile if a
replacement was made.
(2)t label
Test. Branch to the : command bearing the label if any
substitutions 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.
(2)x Exchange the contents of the pattern and hold spaces.
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SED(1) SED(1)
(2)y/string1/string2/
Transform. Replace all occurrences of characters in string1
with the corresponding character in string2. The lengths of
string1 and string2 must be equal.
(2)! function
Don't. Apply the function (or group, if function is {) only to
lines not selected by the address(es).
(0): label
This command does nothing; it bears a label for b and t
commands to branch to.
(1)= Place the current line number on the standard output as a line.
(2){ Execute the following commands through a matching } 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 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.
awk(1), ed(1), grep(1), regcomp(5).
PPPPaaaaggggeeee 4444 [ Back ]
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