Commands using perl (369)

  • changes THIS to THAT in all files matching fileglob* without using secondary files


    2
    perl -pi -e 's/THIS/THAT/g' fileglob*
    elofland · 2009-02-05 19:19:52 60

  • 2
    perl -pe 's/.+;//' ~/.zsh_history | sort | uniq -c | sort -r|head -10
    aoiaoi · 2009-02-06 15:24:32 167

  • 2
    perl -pe 's/\d+/++$n/e' file.txt
    mikeda · 2009-02-17 14:51:31 6
  • Insert a comma where necessary when counting large numbers. I needed to separate huge amounts of packets and after 12+ hours of looking in a terminal, I wanted it in readable form. Show Sample Output


    2
    perl -pe '$_=reverse;s/\d{3}(?=\d)(?!.*?\.)/$&,/g;$_=reverse'
    sil · 2009-02-18 16:34:18 15
  • Finds the string in every file in an entire directory and all its subdirectories and replaces it with a new string. Especially useful when changing a machine's IP address or hostname - run it on /etc.


    2
    perl -pi -e's/<what to find>/<what to replace it with>/g' `grep -Rl <what to find> /<dir>/*`
    adampbell · 2009-02-26 19:14:39 8

  • 2
    find $HOME -type f -print | perl -wnlaF'/' -e 'BEGIN{ print "#EXTM3U"; } /.+\.wmv$|.+\.mpg$|.+\.vob$/i and print "#EXTINF:$F[-1]\nfile://$&";' > movies.m3u
    ishiduca · 2009-02-28 12:17:41 4

  • 2
    perl -ne 'while (/([0-9]+\.){3}[0-9]+/g) {print "$&\n"};' file.txt
    P17 · 2009-04-01 13:49:46 6
  • There was another line that was dependent on having un-named screen sessions. This just wouldn't do. This one works no matter what the name is. A possible improvement would be removing the perl dependence, but that doesn't effect me.


    2
    for i in `screen -ls | perl -ne'if(/^\s+\d+\.([^\s]+)/){print $1, " "}'`; do gnome-terminal -e "screen -x $i"; done
    hank · 2009-04-25 22:39:24 7
  • Replace 'this' with 'that'


    2
    perl -p -i -e 's/this/that/g' filename
    rader5 · 2009-08-09 20:53:50 8
  • When you have one of those (log)files that only has epoch for time (since no one will ever look at them as a date) this is a way to get the human readable date/time and do further inspection. Mostly perl-fu :-/


    2
    perl -F' ' -MDate::Format -pale 'substr($_, index($_, $F[1]), length($F[1]), time2str("%C", $F[1]))' file.log
    coffeeaddict_nl · 2009-08-13 13:57:33 4

  • 2
    perl -e 'print scalar(gmtime(1234567890)), "\n"'
    andrew112358 · 2009-08-25 15:00:52 4

  • 2
    wget 'link of a Picasa WebAlbum' -O - |perl -e'while(<>){while(s/"media":{"content":\[{"url":"(.+?\.JPG)//){print "$1\n"}}' |wget -w1 -i -
    aciancone · 2009-09-27 14:36:27 7
  • Once I wrote a command line calculator program in C, then I found this... and added to it a bit. For ease of use I normally use this in a tiny Perl program (which I call pc for 'Perl Calculator') #!/usr/bin/perl -w die "Usage: $0 MATHS\n" unless(@ARGV);for(@ARGV){s/x/*/g;s/v/sqrt /g;s/\^/**/g}; print eval(join('',@ARGV)),$/; It handles square roots, power, modulus: pc 1+2 (1 plus 2) 3 pc 3x4 (3 times 4) 12 pc 5^6 (5 to the power of 6) 15625 pc v 49 ( square root of 49 ) 7 pc 12/3 (12 divided by 3) 4 pc 19%4 (19 modulus 4) 3 (you can string maths together too) pc 10 x 10 x 10 1000 pc 10 + 10 + 10 / 2 25 pc 7 x v49 49 Show Sample Output


    2
    perl -e 'for(@ARGV){s/x/*/g;s/v/sqrt /g;s/\^/**/g};print eval(join("",@ARGV)),$/;'
    JohnGH · 2009-12-21 21:03:27 9
  • This is a big time saver for me. I often grep source code and need to edit the findings. A single highlight of the mouse and middle mouse click (in gnome terminal) and I'm editing the exact line I just found. The color highlighting helps interpret the data.


    2
    mgc() { grep --exclude=cscope* --color=always -rni $1 . |perl -pi -e 's/:/ +/' |perl -pi -e 's/^(.+)$/vi $1/g' |perl -pi -e 's/:/ /'; }
    stinkerweed999 · 2010-01-26 17:00:01 4
  • Like command #4845, prints score, number of entries, and average score.


    2
    username=bartonski;curl -s http://www.commandlinefu.com/commands/by/$username/json|perl -e 'BEGIN{$s=0;$n=0};END{print "Score: $s\nEntries: $n\nMean: ";printf "%3.2f\n",$s/$n}' -0173 -nae 'foreach $f (@F){if($f =~ /"votes":"(-*\d+)"/){$s += $1; $n++;}}'
    bartonski · 2010-02-16 01:03:29 4
  • Requires Net::Twitter. Just replace the double quoted strings with the appropriate info.


    2
    perl -MNet::Twitter -e '$nt = Net::Twitter->new(traits => [qw/API::REST/], username => "YOUR USERNAME", password => "YOUR PASSWORD"); $ud = $nt->update("YOUR TWEET");'
    dbbolton · 2010-06-16 19:46:05 4
  • **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


    2
    diff <(perl -wpl -e '$_ =~ s/^\s+|\s+$//g ;' file1) <(perl -wpl -e '$_ =~ s/^\s+|\s+$//g ;' file2)
    jemptymethod · 2010-10-06 19:14:42 5
  • If you are in an environment where you don't have the base64 executable or MIME tools available, this can be very handy for salvaging email attachments when the headers are mangled but the encoded document itself is intact.


    2
    perl -MMIME::Base64 -ne 'print decode_base64($_)' < file.txt > out
    dmmst19 · 2010-12-13 23:35:20 3
  • This is a naive way of finding source code comments in source code files that use C-like comments: // and /*...*/


    2
    perl -e 'my $in_comment = 0; while (<>) { $in_comment = 1 if m{\Q/*\E}; print if $in_comment; $in_comment = 0 if m{\Q*/\E}; }' *.cpp
    doherty · 2011-07-08 00:17:27 4

  • 2
    route -n | perl -ne '$ANY="0.0.0.0"; /^$ANY/ and split /\s+/ and print "Gateway to the World: ",($_[1]!=$ANY)?$_[1]:(`ip address show $_[$#_]`=~/peer ([0-9\.]+)/ and $1),", via $_[$#_].\n"'
    bandie91 · 2011-09-13 08:05:58 5

  • 2
    perl -le 'print$_%3?$_%5?$_:"Buzz":$_%5?"Fizz":"FizzBuzz"for 1..100'
    depesz · 2012-01-10 13:10:30 5

  • 2
    perl -i -ne 'print if $. == 3..5' <filename>
    bashrc · 2012-01-27 23:15:10 4
  • - excel date compatible with a separate hour field - added a fixed 1 for easier request counter aggregation - split URL in directory, filename, fileext, query - used with tomcat valve with response bytes replaced by elapsed time Show Sample Output


    2
    #(see sample) $ cat x | perl -pe 'BEGIN{ print "TIME;...\n"; } s!(\S+) - (\S+) - \[(\d\d)/(\S\S\S)/(\S+):(\d\d):(\d\d:\d\d) \S+\] "(\S+) (.*/)(\S+)(?:\.([^?]*)(\?\S*)?) HTTP/\S+" (\d+) (\S+)!$3-$4-$5 $6:$7;$6;$2;$1;$8;$13;1;$14;$11;$10;$9;$12;!' > x.csv
    hute37 · 2012-02-10 16:58:50 3
  • Nasty perl one-liner that provides a sparkline of ping times. If you want a different history than the last 30, just put that value in. It (ab)uses unicode to draw the bars, inspired by https://github.com/joemiller/spark-ping . It's not the most bug-free piece of code, but what it lacks in robustness it makes up for in capability. :) If anyone has any ideas on how to make it more compact or better, I'd love to hear them. I included a ping to google in the command just as an example (and burned up 10 chars doing it!). You should use it with: $ ping example.com | $SPARKLINE_PING_COMMAND Show Sample Output


    2
    ping g.co|perl -ne'$|=/e=(\S+)/||next;(push@_,$1)>30&&shift@_;print"\r",(map{"\xe2\x96".chr(128+7*$_/(sort{$b<=>$a}@_)[0])." "}@_),"$1ms"'
    bartgrantham · 2012-07-06 22:42:06 3
  • 1.- Enter into the playlist path. 2.- Run the command. 3.- Playlists created!


    2
    wget -q -O - http://listen.di.fm/public2 | sed 's/},{/\n/g' | perl -n -e '/"key":"([^"]*)".*"playlist":"([^"]*)"/; print "$1\n"; system("wget -q -O - $2 | grep -E '^File' | cut -d= -f2 > di_$1.m3u")'
    Zort · 2013-02-20 03:37:41 9
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convert a .wmv to a .avi

Simple Video Surveillance by email
This takes a picture (with the web cam) every 5 minutes, and send the picture to your e-mail. Some systems support mail -a "References: " so that all video surveillance emails are grouped in a single email thread. To keep your inbox clean, it is still possible to filter and move to trash video surveillance emails (and restore these emails only if you really get robbed!) For instance with Gmail, emails sent to me+trash@gmail.com can be filtered with "Matches: DeliveredTo:me+trash@gmail.com"

Print average GPU core temperature

Create Encrypted WordPress MySQL Backup without any DB details, just the wp-config.php
The coolest way I've found to backup a wordpress mysql database using encryption, and using local variables created directly from the wp-config.php file so that you don't have to type them- which would allow someone sniffing your terminal or viewing your shell history to see your info. I use a variation of this for my servers that have hundreds of wordpress installs and databases by using a find command for the wp-config.php file and passing that through xargs to my function.

Commit command to history file immedeately after execution
This could be added to .bashrc. Background: Linux usually saves history only on clean exit of shell. If shell ends unclean, history is lost. Also numerous terminals might confuse their history. With this variable set, history is immedeately written, accessible to all other open shells.

clone directory structure
dir1 and all its subdirs and subdirs of subdirs ... but *no files* will be copied to dir2 (not even symbolic links of files will be made). To preserve ownerships & permissions: $ cp -Rps dir1 dir2 Yes, you can do it with $ rsync -a --include '*/' --exclude '*' /path/to/source /path/to/dest too, but I didn't test if this can handle attributes correctly (experiment rsync command yourself with --dry-run switch to avoid harming your file system) You must be in the parent directory of dir1 while executing this command (place dir2 where you will), else soft links of files in dir2 will be made. I couldn't find how to avoid this "limitation" (yet). Playing with recursive unlink command loop maybe? PS. Bash will complain, but the job will be done.

Using numsum to sum a column of numbers.
numsum is part of of the num-utils package, which is available in some Linux distros and can also be downloaded at http://suso.suso.org/xulu/Num-utils. It contains about 10 different programs for dealing with numbers from the command line. Obviously you can do a lot of things that the num-utils programs do in awk, sed, bash, perl scripts, but num-utils are there so that you don't have to remember the syntax for more complex operations and can just think: compute the sum, average, boundary numbers, etc.

sshfs usage
you can use this command for mounting local directory to a remost directory..

Display current time in requested time zones.
The time zone names come from the tz database which is usually found at /usr/share/zoneinfo.

Decrypt passwords from Google Chrome and Chromium.
Read this before you down voting and comment that it is not working -> Wont work on latest versions ~75> since database file is locked and has to be decrypted. This is useful if you have an old hdd with a chrome installation and want to decrypt your old passwords fast.


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