sed(1) (Essential Utilities) sed(1)
NAME
sed - stream editor
SYNOPSIS
sed [-n] [-e script] [-f sfile] [file ...]
DESCRIPTION
sed copies the named file (standard input default) to the standard
output, edited according to a script of commands. The -f option
causes the script to be taken from file sfile; these 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.
A script consists of editing commands, one per line, of the following
form:
[ address [ , address ] ] function [ arguments ]
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 under -n) and deletes the pattern space.
Some of the commands use a hold space to save all or part of the
pattern space for subsequent retrieval.
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 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.) Thereafter the process is repeated,
looking again for the first address.
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sed(1) (Essential Utilities) sed(1)
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\
text Change. Delete the pattern space. 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.
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sed(1) (Essential Utilities) sed(1)
(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 nth 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. 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.
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sed(1) (Essential Utilities) sed(1)
(2)y/string1/string2/
Transform. Replace all occurrences of characters in
string1 with the corresponding characters in string2.
string1 and string2 must have the same number of
characters.
(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 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.
SEE ALSO
awk(1), ed(1), grep(1).
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