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发表于 2011-8-25 00:01
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man sed的输出内容.
看不懂英文?
SED(1) User Commands SED(1)
NAME
sed - stream editor for filtering and transforming text
SYNOPSIS
sed [OPTION]... {script-only-if-no-other-script} [input-file]...
DESCRIPTION
Sed is a stream editor. A stream editor is used to perform basic text transforma‐
tions on an input stream (a file or input from a pipeline). While in some ways
similar to an editor which permits scripted edits (such as ed), sed works by mak‐
ing only one pass over the input(s), and is consequently more efficient. But it
is sed's ability to filter text in a pipeline which particularly distinguishes it
from other types of editors.
-n, --quiet, --silent
suppress automatic printing of pattern space
-e script, --expression=script
add the script to the commands to be executed
-f script-file, --file=script-file
add the contents of script-file to the commands to be executed
--follow-symlinks
follow symlinks when processing in place
-i[SUFFIX], --in-place[=SUFFIX]
edit files in place (makes backup if extension supplied)
-l N, --line-length=N
specify the desired line-wrap length for the `l' command
--posix
disable all GNU extensions.
-r, --regexp-extended
use extended regular expressions in the script.
-s, --separate
consider files as separate rather than as a single continuous long stream.
-u, --unbuffered
load minimal amounts of data from the input files and flush the output buf‐
fers more often
--help
display this help and exit
--version
output version information and exit
If no -e, --expression, -f, or --file option is given, then the first non-option
argument is taken as the sed script to interpret. All remaining arguments are
names of input files; if no input files are specified, then the standard input is
read.
GNU sed home page: <http://www.gnu.org/software/sed/>. General help using GNU
software: <http://www.gnu.org/gethelp/>. E-mail bug reports to: <bug-gnu-
[email]utils@gnu.org[/email]>. Be sure to include the word ``sed'' somewhere in the ``Subject:''
field.
COMMAND SYNOPSIS
This is just a brief synopsis of sed commands to serve as a reminder to those who
already know sed; other documentation (such as the texinfo document) must be con‐
sulted for fuller descriptions.
Zero-address ``commands''
: label
Label for b and t commands.
#comment
The comment extends until the next newline (or the end of a -e script frag‐
ment).
} The closing bracket of a { } block.
Zero- or One- address commands
= Print the current line number.
a \
text Append text, which has each embedded newline preceded by a backslash.
i \
text Insert text, which has each embedded newline preceded by a backslash.
q [exit-code]
Immediately quit the sed script without processing any more input, except
that if auto-print is not disabled the current pattern space will be
printed. The exit code argument is a GNU extension.
Q [exit-code]
Immediately quit the sed script without processing any more input. This is
a GNU extension.
r filename
Append text read from filename.
R filename
Append a line read from filename. Each invocation of the command reads a
line from the file. This is a GNU extension.
Commands which accept address ranges
{ Begin a block of commands (end with a }).
b label
Branch to label; if label is omitted, branch to end of script.
t label
If a s/// has done a successful substitution since the last input line was
read and since the last t or T command, then branch to label; if label is
omitted, branch to end of script.
T label
If no s/// has done a successful substitution since the last input line was
read and since the last t or T command, then branch to label; if label is
omitted, branch to end of script. This is a GNU extension.
c \
text Replace the selected lines with text, which has each embedded newline pre‐
ceded by a backslash.
d Delete pattern space. Start next cycle.
D Delete up to the first embedded newline in the pattern space. Start next
cycle, but skip reading from the input if there is still data in the pat‐
tern space.
h H Copy/append pattern space to hold space.
g G Copy/append hold space to pattern space.
x Exchange the contents of the hold and pattern spaces.
l List out the current line in a ``visually unambiguous'' form.
l width
List out the current line in a ``visually unambiguous'' form, breaking it
at width characters. This is a GNU extension.
n N Read/append the next line of input into the pattern space.
p Print the current pattern space.
P Print up to the first embedded newline of the current pattern space.
s/regexp/replacement/
Attempt to match regexp against the pattern space. If successful, replace
that portion matched with replacement. The replacement may contain the
special character & to refer to that portion of the pattern space which
matched, and the special escapes \1 through \9 to refer to the correspond‐
ing matching sub-expressions in the regexp.
w filename
Write the current pattern space to filename.
W filename
Write the first line of the current pattern space to filename. This is a
GNU extension.
y/source/dest/
Transliterate the characters in the pattern space which appear in source to
the corresponding character in dest.
Addresses
Sed commands can be given with no addresses, in which case the command will be
executed for all input lines; with one address, in which case the command will
only be executed for input lines which match that address; or with two addresses,
in which case the command will be executed for all input lines which match the
inclusive range of lines starting from the first address and continuing to the
second address. Three things to note about address ranges: the syntax is
addr1,addr2 (i.e., the addresses are separated by a comma); the line which addr1
matched will always be accepted, even if addr2 selects an earlier line; and if
addr2 is a regexp, it will not be tested against the line that addr1 matched.
After the address (or address-range), and before the command, a ! may be
inserted, which specifies that the command shall only be executed if the address
(or address-range) does not match.
The following address types are supported:
number Match only the specified line number.
first~step
Match every step'th line starting with line first. For example, ``sed -n
1~2p'' will print all the odd-numbered lines in the input stream, and the
address 2~5 will match every fifth line, starting with the second. first
can be zero; in this case, sed operates as if it were equal to step. (This
is an extension.)
$ Match the last line.
/regexp/
Match lines matching the regular expression regexp.
\cregexpc
Match lines matching the regular expression regexp. The c may be any char‐
acter.
GNU sed also supports some special 2-address forms:
0,addr2
Start out in "matched first address" state, until addr2 is found. This is
similar to 1,addr2, except that if addr2 matches the very first line of
input the 0,addr2 form will be at the end of its range, whereas the 1,addr2
form will still be at the beginning of its range. This works only when
addr2 is a regular expression.
addr1,+N
Will match addr1 and the N lines following addr1.
addr1,~N
Will match addr1 and the lines following addr1 until the next line whose
input line number is a multiple of N.
REGULAR EXPRESSIONS
POSIX.2 BREs should be supported, but they aren't completely because of perfor‐
mance problems. The \n sequence in a regular expression matches the newline char‐
acter, and similarly for \a, \t, and other sequences.
BUGS
E-mail bug reports to [email]bonzini@gnu.org[/email]. Be sure to include the word ``sed'' some‐
where in the ``Subject:'' field. Also, please include the output of ``sed --ver‐
sion'' in the body of your report if at all possible.
COPYRIGHT
Copyright © 2009 Free Software Foundation, Inc.
This is free software; see the source for copying conditions. There is NO war‐
ranty; not even for MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE, to the
extent permitted by law.
GNU sed home page: <http://www.gnu.org/software/sed/>. General help using GNU
software: <http://www.gnu.org/gethelp/>. E-mail bug reports to: <bug-gnu-
[email]utils@gnu.org[/email]>. Be sure to include the word ``sed'' somewhere in the ``Subject:''
field.
SEE ALSO
awk(1), ed(1), grep(1), tr(1), perlre(1), sed.info, any of various books on sed,
the sed FAQ (http://sed.sf.net/grabbag/tutorials/sedfaq.txt),
http://sed.sf.net/grabbag/.
The full documentation for sed is maintained as a Texinfo manual. If the info and
sed programs are properly installed at your site, the command
info sed
should give you access to the complete manual.
sed version 4.2.1 June 2009 SED(1) |
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发表于 2011-8-19 17:13
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发表于 2011-8-19 22:13
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