sed
stream editor for filtering and transforming text
see also :
awk - ed - grep - tr
Synopsis
sed
[OPTION]... {script-only-if-no-other-script}
[input-file]...
add an example, a script, a trick and tips
examples
line=$(echo "$line" | sed 's/\//\\\//g');
will escape all slashes in the variable line
example added by LeBerger
sed -i 's/[ ]\+/ /g'
will replace one or more space by one space, directly in the file.
In other word, it doesn't output the resulting string, but edit directly the file
example added by LeBerger
source
How to replace a list of strings by another list
This is basically your first idea, but with the substitution
commands put into a file, so they’re more manageable:
tmpfile=/tmp/Asasuser.$$
exec 3< fileA
exec 4< fileB
while read –r astring <&3
do
read –r bstring <&4
echo "s/$astring/$bstring/" >> "$tmpfile"
done
exec 3<&- 4<&-
sed –f "$tmpfile" file1 > out
rm –f "$tmpfile"
This assumes that fileA and fileB have
the same number of lines (and that that number is greater than
zero) and that neither of them has any unescaped /
characters.
line=$(echo "$line" | sed 's/\//\\\//g');
will escape all slashes in the variable line
example added by LeBerger
sed -i 's/[ ]\+/ /g'
will replace one or more space by one space, directly in the file.
In other word, it doesn't output the resulting string, but edit directly the file
example added by LeBerger
source
ifconfig | sed -f task_5.sed
source
sed -Ef ld_sed_pass_1 $1 | sed -f ld_sed_pass_2
source
sed: how to replace line if found or append to end of file if not found?
It's a bit easier in awk, although the "in place editing" is not
automatic:
awk -v varname="FOOBAR" -v newval="newvalue" '
BEGIN {FS = OFS = "="}
$1 == varname {$2 = newval; found = 1}
{print}
END {if (! found) {print varname, newval}}
' file > tempfile &&
mv tempfile file
source
How to Remove the Last 2 Lines of a Very Large File
Try VIM...I'm not sure if it will do the trick or not, as I've
never used it on such a big file, but I've used it on smaller
larger files in the past give it try.
source
Edit first line of large text file
You can use less to see what you want to edit and
use sed to make the changes. This way you edit
without loading the entire file.
Another way is to split the file, edit and join again:
split -b 10000k <file>
and to join:
cat xa* > <file>
source
Search for files with more than one term (grep, awk?)
You can use either the -e or -f options
to search for multiple expressions (from man grep):
-e PATTERN, --regexp=PATTERN
Use PATTERN as the pattern. This can be used to specify
multiple search patterns, or to protect a pattern beginning with
a hyphen (-). (-e is specified by POSIX.)
-f FILE, --file=FILE
Obtain patterns from FILE, one per line. The empty file
contains zero patterns, and therefore matches nothing. (-f is
specified by POSIX.)
So you would use this as:
$ grep -e termA -e termB *
source
List only the device names of all available network interfaces
to just print the first column:
netstat -a | awk '{print $1}'
you can incorporate other rules in awk to add or remove entries
as needed.
EDIT: same goes with ifconfig (like Doug pointed out)
ifconfig | awk '{print $1}'
This is an example excluding the 'lo' interface
ifconfig | awk '{if ($1 != lo) print $1}'
source
SQL like group by and sum for text files in command line?
You could a use a few lines of Lua to acheive this. Lua is available on a wide
range of platforms including Windows and Linux.
-- Quick and dirty - no error checking, unsorted output
io.input('huge_text_file.txt')
results = {}
for line in io.lines() do
for text, number in string.gmatch(line, '(%w+)%s+(%d+)') do
results[text] = (results[text] or 0) + number
end
end
for text, number in pairs(results) do
print(text, number)
end
You can sort the output using any sort utility or a few more
lines of Lua.
source
SED: How can I print every line after first instance of string using Sed?
Use a regular expression in the address:
sed -n '/^16:30/,$p'
or
sed '/^16:30/,$!d'
source
Prefix all lines with the first word in a file
Perl solution:
perl -pe 'print $prefix; ($prefix) = /^(.+? )/ if 1..1' INPUT.TXT
source
Using sed to Download ComboFix automatically
That's funny: I just went to http://www.bleepingcomputer.com/download/combofix/dl/12/
and found
<a
href='http://download.bleepingcomputer.com/dl/587c6038..../..../ComboFix.exe'>click
here</a>.
i.e., the URL is delimited by single quotes (') rather
than double quotes (") (which is what your
sed command is looking for).
description
Sed is a
stream editor. A stream editor is used to perform basic text
transformations 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 making 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.
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
when processing in place
-i[SUFFIX],
--in-place[=SUFFIX]
edit files in
place (makes backup if extension supplied)
specify the
desired line-wrap length for the ’l’ command
disable all GNU
extensions.
use extended
regular expressions in the script.
consider files
as separate rather than as a single continuous long
stream.
load minimal
amounts of data from the input files and flush the output
buffers 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-utils[:at:]gnu[:dot:]org>. Be
sure to include the word ’’sed’’
somewhere in the ’’Subject:’’
field.
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 character.
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.
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 consulted
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 fragment).
}
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.
c \
text
Replace the selected lines with text, which has each
embedded newline preceded 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 pattern space.
h H
Copy/append pattern space to hold space.
g G
Copy/append hold space to pattern space.
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 corresponding
matching sub-expressions in the regexp.
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.
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.
x
Exchange the contents of the hold and pattern spaces.
y/source/dest/
Transliterate the characters in the pattern space which appear in
source to the corresponding character in dest.
copyright
Copyright © 2009 Free Software Foundation, Inc.
This is free software; see the source for copying conditions.
There is NO warranty; 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-utils[:at:]gnu[:dot:]org>. Be sure to include the
word ’’sed’’ somewhere in the ’’Subject:’’ field.
regular expressions
POSIX.2 BREs should be supported, but they aren’t
completely because of performance problems. The \n
sequence in a regular expression matches the newline character,
and similarly for \a, \t, and other sequences.
bugs
E-mail bug
reports to bonzini[:at:]gnu[:dot:]org. Be sure to include the
word ’’sed’’ somewhere in the
’’Subject:’’ field. Also, please
include the output of ’’sed
--version’’ in the body of your report if at all
possible.
see also
awk ,
ed , grep , tr ,
perlre, 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.