Commands using perl (369)

  • modify a file in place with perl

    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
  • The top ten commands you use

    Show Sample Output


    2
    perl -pe 's/.+;//' ~/.zsh_history | sort | uniq -c | sort -r|head -10
    aoiaoi · 2009-02-06 15:24:32 166
  • re-assign line numbers

    Show Sample Output


    2
    perl -pe 's/\d+/++$n/e' file.txt
    mikeda · 2009-02-17 14:51:31 6
  • Comma insertions

    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
  • Recursive Search and Replace

    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
  • make a list of movies(.m3u).


    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
  • Prints any IP out of a file


    2
    perl -ne 'while (/([0-9]+\.){3}[0-9]+/g) {print "$&\n"};' file.txt
    P17 · 2009-04-01 13:49:46 6
  • Connect to all running screen instances

    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 Every occurrence of a word in a file

    Replace 'this' with 'that'


    2
    perl -p -i -e 's/this/that/g' filename
    rader5 · 2009-08-09 20:53:50 8
  • show the real times iso of epochs for a given column

    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
  • convert unixtime to human-readable


    2
    perl -e 'print scalar(gmtime(1234567890)), "\n"'
    andrew112358 · 2009-08-25 15:00:52 4
  • Go get those photos from a Picasa album


    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
  • A command line calculator in Perl

    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
  • Recursively grep for string and format output for vi(m)

    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
  • Get your commandlinefu points (upvotes - downvotes)

    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
  • Update twitter with Perl

    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
  • 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


    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
  • Decode base64-encoded file in one line of Perl

    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
  • Find C/C++ source code comments

    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
  • Find default gateway (proper at ppp connections too)


    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
  • FizzBuzz One-liner


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

    Show Sample Output


    2
    perl -i -ne 'print if $. == 3..5' <filename>
    bashrc · 2012-01-27 23:15:10 4
  • Apache CLF access log format to CSV converter

    - 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
  • Text graphing ping output filter

    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
  • MPD + Digitally Imported

    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 seconds to [DD:][HH:]MM:SS
Converts any number of seconds into days, hours, minutes and seconds. sec2dhms() { declare -i SS="$1" D=$(( SS / 86400 )) H=$(( SS % 86400 / 3600 )) M=$(( SS % 3600 / 60 )) S=$(( SS % 60 )) [ "$D" -gt 0 ] && echo -n "${D}:" [ "$H" -gt 0 ] && printf "%02g:" "$H" printf "%02g:%02g\n" "$M" "$S" }

Decode base64-encoded file in one line of Perl
Another option is openssl.

Get AWS temporary credentials ready to export based on a MFA virtual appliance
You might want to secure your AWS operations requiring to use a MFA token. But then to use API or tools, you need to pass credentials generated with a MFA token. This commands asks you for the MFA code and retrieves these credentials using AWS Cli. To print the exports, you can use: `awk '{ print "export AWS_ACCESS_KEY_ID=\"" $1 "\"\n" "export AWS_SECRET_ACCESS_KEY=\"" $2 "\"\n" "export AWS_SESSION_TOKEN=\"" $3 "\"" }'` You must adapt the command line to include: * $MFA_IDis ARN of the virtual MFA or serial number of the physical one * TTL for the credentials

Wait for file to stop changing
Here's a way to wait for a file (a download, a logfile, etc) to stop changing, then do something. As written it will just return to the prompt, but you could add a "; echo DONE" or whatever at the end. This just compares the full output of "ls" every 10 seconds, and keeps going as long as that output has changed since the last interval. If the file is being appended to, the size will change, and if it's being modified without growing, the timestamp from the "--full-time" option will have changed. The output of just "ls -l" isn't sufficient since by default it doesn't show seconds, just minutes. Waiting for a file to stop changing is not a very elegant or reliable way to measure that some process is finished - if you know the process ID there are much better ways. This method will also give a false positive if the changes to the target file are delayed longer than the sleep interval for any reason (network timeouts, etc). But sometimes the process that is writing the file doesn't exit, rather it continues on doing something else, so this approach can be useful if you understand its limitations.

Create a simple playlist sort by Genre using mp3info

Temporarily ignore known SSH hosts
you may create an alias also, which I did ;-) alias sshu="ssh -o UserKnownHostsFile=/dev/null "

dd with progress bar and statistics to gzipped image
This is a useful command to backup an sd card with relative total size for piping to pv with a progressbar

ThePirateBay.org torrent search
This one-liner greps first 30 direct URLs for .torrent files matching your search querry, ordered by number of seeds (descending; determined by the second number after your querry, in this case 7; for other options just check the site via your favorite web-browser). You don't have to care about grepping the torrent names as well, because they are already included in the .torrent URL (except for spaces and some other characters replaced by underscores, but still human-readable). Be sure to have some http://isup.me/ macro handy (someone often kicks the ethernet cables out of their servers ;) ). I've also coded a more user-friendly ash (should be BASH compatible) script, which also lists the total size of download and number of seeds/peers (available at http://saironiq.blogspot.com/2011/04/my-shell-scripts-4-thepiratebayorg.html - may need some tweaking, as it was written for a router running OpenWrt and transmission). Happy downloading!

print shared library dependencies
May be used on (embedded) systems lack ldd

Create new user with home dir and given password
The crypt function takes a password, key, as a string, and a salt character array which is described below, and returns a printable ASCII string which starts with another salt. It is believed that, given the output of the function, the best way to find a key that will produce that output is to guess values of key until the original value of key is found. from http://en.wikipedia.org/wiki/Crypt_(Unix)

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