sed(1) sed(1)
NAME
sed - stream editor
SYNOPSIS
sed [-n] [-e script] [-f sfile] [files]
DESCRIPTION
sed copies the named files (standard input default) to the
standard output, edited according to a script of commands.
The -f flag option causes the script to be taken from file
sfile; these flag options accumulate. If there is just one
-e flag option and no -f flag options, the flag -e may be
omitted. The -n flag option suppresses the default output.
A script consists of editing commands, one per line, of the
following form:
[address[,address]]function
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 newline embedded in the
pattern space.
A period . matches any character except the terminal
newline 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
Page 1 (last mod. 1/16/87)
sed(1) sed(1)
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.
The text argument consists of one or more lines, all but the
last of which end with (Reg.)to hide the newline.
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. 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)l List the pattern space on the standard output in
an unambiguous form. Non-printing characters
are spelled in two-digit ASCII 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 newline. (The current
Page 2 (last mod. 1/16/87)
sed(1) sed(1)
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 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.
(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
Negate 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 the
Page 3 (last mod. 1/16/87)
sed(1) sed(1)
first 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.
EXAMPLE
sed -f sedfile inputfile > filea
will process the inputfile according to the sedfile script,
and place the results in filea.
The sedfile script
4 a\
XXXXXXXXXXXXX
would insert a row of Xs after line 4.
FILES
/bin/sed
SEE ALSO
awk(1), ed(1), grep(1).
WARNING
Operations based on a deleted line are lost. For example, if
you insert text before line 4 and then delete line 4, the
inserted text is lost. Reads at line 0 are actually reads
before line 1, so deleting line 1 erases these reads. Writes
are lost as well, although the filename is created.
Page 4 (last mod. 1/16/87)