Hide

What's this?

commandlinefu.com is the place to record those command-line gems that you return to again and again.

Delete that bloated snippets file you've been using and share your personal repository with the world. That way others can gain from your CLI wisdom and you from theirs too. All commands can be commented on, discussed and voted up or down.

If you have a new feature suggestion or find a bug, please get in touch via http://commandlinefu.uservoice.com/

Get involved!

You can sign-in using OpenID credentials, or register a traditional username and password.

OpenID
or
Sign in Register

First-time OpenID users will be automatically assigned a username which can be changed after signing in.

Hide

Stay in the loop…

Follow the Tweets.

Every new command is wrapped in a tweet and posted to Twitter. Following the stream is a great way of staying abreast of the latest commands. For the more discerning, there are Twitter accounts for commands that get a minimum of 3 and 10 votes - that way only the great commands get tweeted.

» http://twitter.com/commandlinefu
» http://twitter.com/commandlinefu3
» http://twitter.com/commandlinefu10

Subscribe to the feeds.

Use your favourite RSS aggregator to stay in touch with the latest commands. There are feeds mirroring the 3 Twitter streams as well as for virtually every other subset (users, tags, functions,…):

Subscribe to the feed for:

Hide

News

2011-03-12 - Confoo 2011 presentation
Slides are available from the commandlinefu presentation at Confoo 2011: http://presentations.codeinthehole.com/confoo2011/
2011-01-04 - Moderation now required for new commands
To try and put and end to the spamming, new commands require moderation before they will appear on the site.
2010-12-27 - Apologies for not banning the trolls sooner
Have been away from the interwebs over Christmas. Will be more vigilant henceforth.
2010-09-24 - OAuth and pagination problems fixed
Apologies for the delay in getting Twitter's OAuth supported. Annoying pagination gremlin also fixed.
Hide

Tags

Hide

Functions

Hide

Credits

Site by David Winterbottom (user root).

Commands tagged perl

Commands tagged perl from sorted by
Terminal - Commands tagged perl - 156 results
pcharc(){ perl -e 'for (0..255) {$_ = chr($_); print if /['$1']/}' | cat -v; echo;}
2010-11-13 00:32:41
User: putnamhill
Functions: cat perl
Tags: perl
1
Up
Down
print character classes

Today I needed a way to print various character classes to use as input for a program I was writing. Also a nice way to visualize character classes.

Show sample output | Comments (1) | Add to favourites | Report as malicious | Submit alternative | Report as a duplicate
pcregrep --color -M -N CRLF "owa_pattern\.\w+\W*\([^\)]*\)" source.sql
2010-11-11 12:53:40
User: hute37
Tags: perl grep regex
0
Up
Down
Source multiline grep with pcregrep

grep multiline in Perl regexp syntax with pcregrep

Show sample output | Comments (2) | Add to favourites | Report as malicious | Submit alternative | Report as a duplicate
git status | perl -F'\s' -nale 'BEGIN { $a = 0 }; $a = 1 if $_ =~ /changed but not updated/i; print $F[-1] if ( $a && -f $F[-1] )'
2010-10-15 07:58:14
User: coffeeaddict_nl
Functions: perl
Tags: status git perl
0
Up
Down
Show the changed files in your GIT repo

Parse the output of git status.

Once the line '# Changed but not updated:' has passed print every last part of the line if it exists on disk.

Comments (1) | Add to favourites | Report as malicious | Submit alternative | Report as a duplicate
diff <(perl -wpl -e '$_ =~ s/^\s+|\s+$//g ;' file1) <(perl -wpl -e '$_ =~ s/^\s+|\s+$//g ;' file2)
2010-10-06 19:14:42
User: jemptymethod
Functions: diff perl
Tags: bash diff perl
2
Up
Down
diff files while disregarding indentation and trailing white space

**NOTE** Tekhne's alternative is much more succinct and its output conforms to the files actual contents rather than with white space removed

My command on the other hand uses bash process substitution (and "Minimal" Perl), instead of files, to first remove leading and trailing white space from lines, before diff'ing the streams. Very useful when differences in indentation, such as in programming source code files, may be irrelevant

Show sample output | Comments (1) | Add to favourites | Report as malicious | Submit alternative | Report as a duplicate
find . -iname '*.jpg' -type f -print0 |perl -0 -ne '$a+=-s $_;END{print "$a\n"}'
2010-09-12 13:14:12
User: unixmonkey10455
Functions: find perl
Tags: size perl find du filesize
1
Up
Down
Summarize size of all files of given type in all subdirectories (in bytes)

This deals nicely with filenames containing special characters and can deal with more files than can fit on a commandline. It also avoids spawning du.

Show sample output | Comments (0) | Add to favourites | Report as malicious | Submit alternative | Report as a duplicate
perl -le 'chomp($w=`which $ARGV[0]`);$_=`file $w`;while(/link\b/){chomp($_=(split/`/,$_)[1]);chop$_;$w.=" -> $_";$_=`file $_`;}print "\n$w";' COMMAND_NAME
2010-07-30 19:26:35
User: dbbolton
Functions: perl
Tags: which perl binary file PATH command
0
Up
Down
Show full path followed by a command

This will show you any links that a command follows (unlike 'file -L'), as well as the ultimate binary or script.

Put the name of the command at the very end; this will be passed to perl as the first argument.

For obvious reasons, this doesn't work with aliases or functions.

Show sample output | Comments (2) | Add to favourites | Report as malicious | Submit alternative | Report as a duplicate
echo "text" | hd
2010-07-20 15:40:52
User: Vilemirth
Functions: echo
Tags: perl hex ascii
1
Up
Down
Convert ascii string to hex
Comments (0) | Add to favourites | Report as malicious | Submit alternative | Report as a duplicate
echo "text" | od -t x1
2010-07-14 14:53:25
User: max_allan
Functions: echo od
Tags: perl hex ascii
0
Up
Down
Convert ascii string to hex

Just use "od" and it can also dump in decimal or octal.

(use -t x1 and not just -x or it confuses the byte order)

There is a load of other formatting options, I'm not sure if you can turn off the address at the start of the line.

Show sample output | Comments (0) | Add to favourites | Report as malicious | Submit alternative | Report as a duplicate
echo -n 'text' | perl -pe 's/(.)/sprintf("\\x%x", ord($1))/eg'
2010-07-14 12:20:42
User: putnamhill
Functions: echo perl
Tags: perl hex ascii
1
Up
Down
Convert ascii string to hex

Here's a version that uses perl. If you'd like a trailing newline:

perl -pe 's/(.)/sprintf("\\x%x", ord($1))/eg; END {print "\n"}'
Comments (0) | Add to favourites | Report as malicious | Submit alternative | Report as a duplicate
perl -e 'print "\x41\x72\x74\x20\x6f\x66\x20\x68\x61\x63\x6b\x69\x6e\x67\x2e\x2e\x2e\n" x 100'
2010-07-11 16:32:00
User: gunslinger_
Functions: perl
Tags: perl shellcode
-15
Up
Down
Art of hacking on perl

Print "Art of hacking..." 100 times by perl

or you can this tools : http://packetstormsecurity.org/shellcode/shellcodeencdec.py.txt

Show sample output | Comments (0) | Add to favourites | Report as malicious | Submit alternative | Report as a duplicate
cat file_with_tabs.txt | perl -pe 's/\t/ /g'
2010-07-11 13:01:22
User: nikc
Functions: cat perl
Tags: cat perl replace
-3
Up
Down
Replace tabs with spaces in file

Replaces tabs in output with spaces. Uses perl since sed seems to work differently across platforms.

Comments (4) | Add to favourites | Report as malicious | Submit alternative | Report as a duplicate
perl -MNet::Twitter -e '$nt = Net::Twitter->new(traits => [qw/API::REST/], username => "YOUR USERNAME", password => "YOUR PASSWORD"); $ud = $nt->update("YOUR TWEET");'
2010-06-16 19:46:05
User: dbbolton
Functions: perl
Tags: net twitter perl update tweet
2
Up
Down
Update twitter with Perl

Requires Net::Twitter. Just replace the double quoted strings with the appropriate info.

Comments (1) | Add to favourites | Report as malicious | Submit alternative | Report as a duplicate
git log -p -z | perl -ln0e 'print if /[+-].*searchedstring/'
2010-06-13 07:41:22
User: takeshin
Functions: perl
Tags: git perl log search
1
Up
Down
See all the commits for which searchstring appear in the git diff
Comments (0) | Add to favourites | Report as malicious | Submit alternative | Report as a duplicate
aptitude purge linux-image | grep ^i | grep -v $(uname -r)
2010-06-11 22:20:42
User: lgallardo
Functions: grep uname
Tags: Debian Linux perl kernel aptitude
-4
Up
Down
Remove all unused kernels with apt-get
Comments (0) | Add to favourites | Report as malicious | Submit alternative | Report as a duplicate
perl -e 'chomp($k=`uname -r`); for (</boot/vm*>) {s/^.*vmlinuz-($k)?//; $l.="linux-image-$_ ";} system "aptitude remove $l";'
2010-06-10 22:16:47
User: dbbolton
Functions: perl
Tags: Debian Linux perl kernel aptitude
1
Up
Down
Remove all unused kernels with apt-get

TIMTOWTDI

Comments (0) | Add to favourites | Report as malicious | Submit alternative | Report as a duplicate
for code in $(find . -type f -name '*.p[ml]'); do perl -c "$code"; done
2010-05-29 23:26:40
User: udog
Functions: find perl
Tags: perl directory syntax
0
Up
Down
Check syntax of all Perl modules or scripts underneath the current directory

Finds all *.p[ml]-files and runs a perl -c on them, checking whether Perl thinks they are syntactically correct

Show sample output | Comments (1) | Add to favourites | Report as malicious | Submit alternative | Report as a duplicate
perl -e 'foreach (@ARGV) {@T=stat($_); print localtime($T[8])." - ".$_."\n"}'
2010-05-20 16:19:17
User: putnamhill
Functions: perl
Tags: perl solaris ls file time
0
Up
Down
Print time and year of file in Solaris (or other Unix ls command that does not have a simple
Comments (0) | Add to favourites | Report as malicious | Submit alternative | Report as a duplicate
perl -e '@F = `ls -1`;while (<@F>){@T = stat($_);print "$_ = " . localtime($T[8]) . "\n";}'
2010-05-20 15:02:51
User: hckhckhck
Functions: perl
Tags: perl solaris ls file time
0
Up
Down
Print time and year of file in Solaris (or other Unix ls command that does not have a simple "--full-list")

Solaris 'ls' command does not have a nice '--full-time' arg to make the time show after a year has passed. So I spit this out quick. It hates spaces in file names.

Show sample output | Comments (0) | Add to favourites | Report as malicious | Submit alternative | Report as a duplicate
perl -MDigest::SHA -e 'print substr( Digest::SHA::sha256_base64( time() ), 0, $ARGV[0] ) . "\n"' <length>
2010-04-30 21:45:46
User: udog
Functions: perl
Tags: perl password random base64 sha256
1
Up
Down
Produce a pseudo random password with given length in base 64

Of course you will have to install Digest::SHA and perl before this will work :)

Maximum length is 43 for SHA256. If you need more, use SHA512 or the hexadecimal form: sha256_hex()

Show sample output | Comments (0) | Add to favourites | Report as malicious | Submit alternative | Report as a duplicate
echo $hex | perl -pe 's/(..)/chr(hex($1))/ge'
2010-04-17 16:24:48
User: dfaulkner
Functions: echo perl
Tags: perl strings hex ascii convert
0
Up
Down
convert a string of hex characters into ascii chars
Comments (0) | Add to favourites | Report as malicious | Submit alternative | Report as a duplicate
perl -i -pe 's/\r/\n/g' file
2010-04-16 13:25:09
User: octopus
Functions: perl
Tags: Linux perl unix
0
Up
Down
Legacy MacOS to Unix text convert using perl
Comments (1) | Add to favourites | Report as malicious | Submit alternative | Report as a duplicate
perldoc perllocal
2010-04-14 10:57:56
User: octopus
Tags: version perl
3
Up
Down
List all installed PERL modules by CPAN

This command will give you the detailed information about the installed perl modules i.e. installed path, Link type, version, files etc.

Show sample output | Comments (1) | Add to favourites | Report as malicious | Submit alternative | Report as a duplicate
curl -s http://api.wunderground.com/auto/wui/geo/ForecastXML/index.xml?query=${@:-<YOURZIPORLOCATION>}|xmlstarlet sel -E utf-8 -t -m //forecast/txt_forecast/forecastday -v fcttext -n
2010-04-13 22:14:48
User: fanfani
Tags: perl curl function weather
-2
Up
Down
Get the weather forecast for the next 24 to 48 for your location.

you can use xmlstarlet to parse output instead of perl

Comments (0) | Add to favourites | Report as malicious | Submit alternative | Report as a duplicate
perl -MStatistics::Descriptive -alne 'my $stat = Statistics::Descriptive::Full->new; $stat->add_data(@F[1..4]); print $stat->variance' filename
2010-04-02 21:16:12
User: alperyilmaz
Functions: perl
Tags: statistics perl math
1
Up
Down
statistics in one line

In this example, file contains five columns where first column is text. Variance is calculated for columns 2 - 5 by using perl module Statistics::Descriptive. There are many more statistical functions available in the module.

Show sample output | Comments (0) | Add to favourites | Report as malicious | Submit alternative | Report as a duplicate
perl -pi -e 's/\r\n?/\n/g'
2010-03-18 17:48:16
User: putnamhill
Functions: perl
Tags: perl
3
Up
Down
Convert files from DOS line endings to UNIX line endings

This method will also convert mac line endings.

Comments (2) | Add to favourites | Report as malicious | Submit alternative | Report as a duplicate