SED(1) BSD SED(1)
NAME
sed - stream editor
SYNOPSIS
sed [ -n ] [ -e script ] [ -f sfile ] [ file ... ]
DESCRIPTION
The stream editor sed copies the named files (standard input is the
default) to the standard output, edited according to a script of
commands.
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.
OPTIONS
-f sfile Take the script of commands from the file sfile; these options
accumulate.
-e script Take the following argument as a command script. If there is
just one -e option and no -foptions, you can omit the flag -e.
-n Suppress the default output; copy only those lines specified by
a p (print) function to the standard output.
ADDRESSES
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, /regular expression/, in the style of ed(1) modified
thus:
The escape sequence \n matches a newline embedded in 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.
Editing commands can be applied only to non-selected pattern spaces
by use of the negation function ! (see below).
FUNCTIONS
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 a \ (backslash) to hide the newline. Backslashes in
text are treated like backslashes in the replacement string of an s
command, and can 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
pattern space with the next line of input.
(2)N Append the next line of input to the pattern space with an
embedded 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
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 can be used
instead 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
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.
(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.
SEE ALSO
ed(1), grep(1), awk(1), lex(1)