Commands using perl (369)

  • This shell function grabs the weather forecast for the next 24 to 48 hours from weatherunderground.com. Replace <YOURZIPORLOCATION> with your zip code or your "city, state" or "city, country", then calling the function without any arguments returns the weather for that location. Calling the function with a zip code or place name as an argument returns the weather for that location instead of your default. To add a bit of color formatting to the output, use the following instead: weather(){ curl -s "http://api.wunderground.com/auto/wui/geo/ForecastXML/index.xml?query=${@:-<YOURZIPORLOCATION>}"|perl -ne '/<title>([^<]+)/&&printf "\x1B[0;34m%s\x1B[0m: ",$1;/<fcttext>([^<]+)/&&print $1,"\n"';} Requires: perl, curl Show Sample Output


    7
    weather(){ curl -s "http://api.wunderground.com/auto/wui/geo/ForecastXML/index.xml?query=${@:-<YOURZIPORLOCATION>}"|perl -ne '/<title>([^<]+)/&&printf "%s: ",$1;/<fcttext>([^<]+)/&&print $1,"\n"';}
    eightmillion · 2010-02-10 01:23:39 16
  • Converts reserved characters in a URI to their percent encoded counterparts. Alternate python version: echo "$url" | python -c 'import sys,urllib;print urllib.quote(sys.stdin.read().strip())' Show Sample Output


    7
    echo "$url" | perl -MURI::Escape -ne 'chomp;print uri_escape($_),"\n"'
    eightmillion · 2010-02-13 00:44:48 32
  • Using perl you can search for patterns spanning several lines, a thing that grep can't do. Append the list of files to above command or pipe a file through it, just as with regular grep. If you add the 's' modifier to the regex, the dot '.' also matches line endings, useful if you don't known how many lines you need are between parts of your pattern. Change '*' to '*?' to make it greedy, that is match only as few characters as possible. See also http://www.commandlinefu.com/commands/view/1764/display-a-block-of-text-with-awk to do a similar thing with awk. Edit: The undef has to be put in a begin-block, or a match in the first line would not be found.


    7
    perl -ne 'BEGIN{undef $/}; print "$ARGV\t$.\t$1\n" if m/(first line.*\n.*second line)/mg'
    hfs · 2010-03-18 15:46:10 33
  • Works only if modules are installed "the right way"


    7
    perl -MExtUtils::Installed -e '$inst = ExtUtils::Installed->new(); @modules = $inst->modules(); print join("\n", @modules);'
    braak · 2010-07-20 15:47:32 9
  • syntax follows regular command line expression. example: let's say you have a directory (with subdirs) that has say 4000 .php files. All of these files were made via script, but uh-oh, there was a typo! if the typo is "let's go jome!" but you meant it to say "let's go home!" find . -name "*.php" | xargs perl -pi -e "s/let\'s\ go\ jome\!/let\'s\ go\ home\!/g" all better :) multiline: find . -name "*.php" | xargs perl -p0777i -e 's/knownline1\nknownline2/replaced/m' indescriminate line replace: find ./ -name '*.php' | xargs perl -pi -e 's/\".*$\"/\new\ line\ content/g' Show Sample Output


    6
    find . -name "*.txt" | xargs perl -pi -e 's/old/new/g'
    neztach · 2009-02-06 00:28:03 28
  • Find all files that contain string XXX in them, change the string from XXX to YYY, make a backup copy of the file and save a list of files changed in /tmp/fileschanged.


    6
    find . -type f -exec grep -l XXX {} \;|tee /tmp/fileschanged|xargs perl -pi.bak -e 's/XXX/YYY/g'
    drossman · 2009-02-16 02:55:23 59

  • 6
    nmap -sS -O -oX /tmp/nmap.xml 10.1.1.0/24 -v -v && perl nmap2nagios.pl -v -r /tmp/10net.xml -o /etc/nagios/10net.cfg
    scubacuda · 2009-02-19 18:42:37 8
  • Finds all directories containing more than 99MB of files, and prints them in human readable format. The directories sizes do not include their subdirectories, so it is very useful for finding any single directory with a lot of large files. Show Sample Output


    6
    du -hS / | perl -ne '(m/\d{3,}M\s+\S/ || m/G\s+\S/) && print'
    Alioth · 2009-03-25 18:06:53 5

  • 6
    perl -lne '$l{$_}=length;END{for(sort{$l{$a}<=>$l{$b}}keys %l){print}}' < /usr/share/dict/words | tail
    grokskookum · 2009-09-10 14:49:03 3
  • Cool but useless. Show Sample Output


    6
    perl -nle 'printf "%0*v8b\n"," ",$_;'
    forcefsck · 2011-01-21 09:20:54 6
  • I use this in my bashrc to expand hosts defined in ~/.ssh/config: function _ssh_completion() { perl -ne 'print "$1 " if /^Host (.+)$/' ~/.ssh/config } complete -W "$(_ssh_completion)" ssh Here's a great article on how to setup your own ~/.ssh/config: http://blogs.perl.org/users/smylers/2011/08/ssh-productivity-tips.html


    6
    perl -ne 'print "$1 " if /^Host (.+)$/' ~/.ssh/config
    bashrc · 2011-08-21 14:51:20 7

  • 5
    u=`curl -d 'dl.start=Free' $(curl $1|perl -wpi -e 's/^.*"(http:\/\/rs.*)" method.*$/$1/'|egrep '^http'|head -n1)|grep "Level(3) \#2"|perl -wpi -e 's/^.*(http:\/\/rs[^\\\\]*).*$/$1/'`;sleep 60;wget $u
    fel1x · 2009-04-01 20:14:41 6
  • Mouse around the title of this item, and note that your cookies are being logged to the console. If I were evil, I could instead send everyone's cookies to my site, and then post up-votes on all my submissions using their cookies, and try to delete every other submission, until clfu was completely pwned by me, redirecting people to malware and porn sites, and so on. Update - now fixed.


    5
    perl -pi -e 's/<a href="#" onmouseover="console.log('xss! '+document.cookie)" style="position:absolute;height:0;width:0;background:transparent;font-weight:normal;">xss</a>/<\/a>/g'
    isaacs · 2009-07-08 22:26:15 30

  • 5
    perl -ne 'split /,/ ; $a+= $_[3]; END {print $a."\n";}' -f ./file.csv
    ioggstream · 2009-08-07 09:35:52 3
  • 'jot' does not come with most *nix distros, so we need to use seq to make it work. This version tested good on Fedora 11.


    5
    for x in `seq 0 25 $(curl "http://www.commandlinefu.com/commands/browse"|grep "Terminal - All commands" |perl -pe 's/.+(\d+),(\d+).+/$1$2/'|head -n1)`; do curl "http://www.commandlinefu.com/commands/browse/sort-by-votes/plaintext/$x" ; done > a.txt
    SuperFly · 2009-08-27 11:02:53 7
  • In this example the command "somecommand" will be executed and sent a SIGALARM signal if it runs for more than 10 seconds. It uses the perl alarm function. It's not 100% accurate on timing, but close enough. I found this really useful when executing scripts and commands that I knew might hang E.g. ones that connect to services that might not be running. Importantly this can be used within a sequential script. The command will not release control until either the command completes or the timeout is hit. Show Sample Output


    5
    perl -e "alarm 10; exec @ARGV" "somecommand"
    jgc · 2009-09-23 12:03:55 9

  • 5
    perl -MCPAN -e 'CPAN::Shell->install(CPAN::Shell->r)'
    grokskookum · 2009-09-24 03:27:12 4
  • Place the regular expression you want to validate between the forward slashes in the eval block. Show Sample Output


    5
    perl -we 'my $regex = eval {qr/.*/}; die "$@" if $@;'
    tlacuache · 2009-10-13 21:50:47 10

  • 5
    perl -pe 's/%([0-9a-f]{2})/sprintf("%s", pack("H2",$1))/eig'
    putnamhill · 2009-11-25 14:32:50 38
  • First we accept a socket and fork the server. Then we overload the new socket as a code ref. This code ref takes one argument, another code ref, which is used as a callback. The callback is called once for every line read on the socket. The line is put into $_ and the socket itself is passed in to the callback. Our callback is scanning the line in $_ for an HTTP GET request. If one is found it parses the file name into $1. Then we use $1 to create an new IO::All file object... with a twist. If the file is executable("-x"), then we create a piped command as our IO::All object. This somewhat approximates CGI support. Whatever the resulting object is, we direct the contents back at our socket which is in $_[0].


    5
    perl -MIO::All -e 'io(":8080")->fork->accept->(sub { $_[0] < io(-x $1 ? "./$1 |" : $1) if /^GET \/(.*) / })'
    Neo23x0 · 2010-03-31 15:03:55 8
  • This will generate 3 paragraphs with random text. Change the 3 to any number. Show Sample Output


    5
    lynx -source http://www.lipsum.com/feed/xml?amount=3|perl -p -i -e 's/\n/\n\n/g'|sed -n '/<lipsum>/,/<\/lipsum>/p'|sed -e 's/<[^>]*>//g'
    houghi · 2010-04-26 17:26:44 5
  • Safe for whitespaces in names.


    5
    dpkg -L iptables | perl -lne 'print if -f && -x'
    depesz · 2010-10-30 15:47:51 7
  • Using tail to follow and standard perl to count and print the lps when lines are written to the logfile.


    5
    tail -f /var/log/logfile|perl -e 'while (<>) {$l++;if (time > $e) {$e=time;print "$l\n";$l=0}}'
    madsen · 2011-06-21 10:28:26 7

  • 4
    find . -type d | perl -nle 'print s,/,/,g," $_"' | sort -n | tail
    sirhc · 2009-02-23 22:52:07 5
  • When Ldapsearch queries an Active directory server, all the dates are shown using a timestamp of 18 digits. This perl regexp decodes them in a more human friendly notation. 11644473600 corresponds to some microsoft epoch. Show Sample Output


    4
    ldapsearch -v -H ldap://<server> -x -D cn=<johndoe>,cn=<users>,dc=<ourdomain>,dc=<tld> -w<secret> -b ou=<lazystaff>,dc=<ourdomain>,dc=<tld> -s sub sAMAccountName=* '*' | perl -pne 's/(\d{11})\d{7}/"DATE-AD(".scalar(localtime($1-11644473600)).")"/e'
    flux · 2009-04-22 00:57:34 5
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Take a screenshot of the window the user clicks on and name the file the same as the window title
In general, this is actually not better than the "scrot -d4" command I'm listing it as an alternative to, so please don't vote it down for that. I'm adding this command because xwd (X window dumper) comes with X11, so it is already installed on your machine, whereas scrot probably is not. I've found xwd handy on boxen that I don't want to (or am not allowed to) install packages on. NOTE: The dd junk for renaming the file is completely optional. I just did that for fun and because it's interesting that xwd embeds the window title in its metadata. I probably should have just parsed the output from file(1) instead of cutting it out with dd(1), but this was more fun and less error prone. NOTE2: Many programs don't know what to do with an xwd format image file. You can convert it to something normal using NetPBM's xwdtopnm(1) or ImageMagick's convert(1). For example, this would work: "xwd | convert fd:0 foo.jpg". Of course, if you have ImageMagick already installed, you'd probably use import(1) instead of xwd. NOTE3: Xwd files can be viewed using the X Window UnDumper: "xwud <foo.xwd". ImageMagick and The GIMP can also read .xwd files. Strangely, eog(1) cannot. NOTE4: The sleep is not strictly necessary, I put it in there so that one has time to raise the window above any others before clicking on it.

follow the content of all files in a directory
The `-q' arg forces tail to not output the name of the current file

sort a JSON blob
For situations where you keep JSON in a VCS and you want your diffs to be sane, such as within a Chef configuration repo.

Change prompt to MS-DOS one (joke)

pass the output of some command to a new email in the default email client
This depends on 'stripansi' and 'urlencode' commands, which exist on my system as these aliases: $ alias stripansi='perl -ple "s/\033\[(?:\d*(?:;\d+)*)*m//g;"' $ alias urlencode='perl -MURI::Escape -ne "\$/=\"\"; print uri_escape \$_"' The `open` command handles URLs on a Mac. Substitute the equivalent for your system (perhaps gnome-open). I don't use system `mail`, so I have this aliased as `mail` and use it this way: $ git show head | mail

github push-ing behind draconian proxies!
If you are behind a restrictive proxy/firewall that blocks port 22 connections but allows SSL on 443 (like most do) then you can still push changes to your github repository. Your .ssh/config file should contain: Host * ForwardX11 no TCPKeepAlive yes ProtocolKeepAlives 30 ProxyCommand /usr/local/bin/proxytunnel -v -p -d %h:443 Host User git Hostname ssh.github.com ChallengeResponseAuthentication yes IdentityFile ~/.ssh/id_rsa IdentitiesOnly yes Basically proxytunnel "tunnels" your ssh connection through port 443. You could also use corkscrew or some other tunneling program that is available in your distro's repository. PS: I generally use "github.com" as the SSH-HOST so that urls of the kind git@github.com:USER/REPO.git work transparently :) You

add a gpg key to aptitute package manager in a ubuntu system
when we add a new package to a aptitude (the debian package manager) we need to add the gpg, otherwise it will show warning / error for missing key

Prepare a commandlinefu command.
This command will format your alias or function to a single line, trimming duplicate white space and newlines and inserting delimiter semi-colons, so it continues to work on a single line.

Which processes are listening on a specific port (e.g. port 80)
swap out "80" for your port of interest. Can use port number or named ports e.g. "http"

Shortcut to find files with ease.
It looks for files that contains the given word as parameter. * case insensitive * matches files containing the given word.


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