SED(1-SysV) RISC/os Reference Manual SED(1-SysV)
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 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 identi-
cal 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
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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.
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. 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 pat-
tern 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
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to the hold space.
(1)i\
text Insert. Place text on the standard out-
put.
(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 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.
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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 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.
(0)# If a # appears as the first character on
the first line of a script file, then
that entire line is treated as a com-
ment, with one exception. If the char-
acter 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.
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SEE ALSO
awk(1), ed(1), grep(1).
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