term% cat index.txt SED(1) General Commands Manual SED(1)
NAME
sed - stream editor
SYNOPSIS
sed [ -n ] [ -e script ] [ -f sfile ] [ file ] ...
DESCRIPTION
Sed copies the named files (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's, 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 pat‐
tern space (unless there is something left after a ‘D' command), ap‐
plies 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.
An address is either a decimal number that counts input lines cumula‐
tively across files, a ‘$' that addresses the last line of input, or a
context address, ‘/regular expression/', in the style of ed(1) modified
thus:
The escape sequence ‘\n' matches a newline embedded in the pat‐
tern 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.
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.
An argument denoted text consists of one or more lines, all but the
last of which end with ‘\' to hide the newline. Backslashes in text
are treated like backslashes in the replacement string of an ‘s' com‐
mand, and may be used to protect initial blanks and tabs against the
stripping that is done on every script line.
An argument denoted rfile or wfile 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. 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 newline. 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)n Copy the pattern space to the standard output. Replace the pat‐
tern space with the next line of input.
(2)N Append the next line of input to the pattern space with an em‐
bedded newline. (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
newline to the standard output.
(1)q Quit. Branch to the end of the script. Do not start a new cy‐
cle.
(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 in‐
stead of ‘/'. For a fuller description see ed(1). Flags is
zero or more of
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 replace‐
ment was made.
(2)t label
Test. Branch to the ‘:' command bearing the label if any sub‐
stitutions 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.
(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' com‐
mands 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.
SEE ALSO
ed(1), grep(1), awk(1), lex(1), cut(1), split(1)
SED(1)