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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Find usb device in realtime
Using this command you can track a moment when usb device was attached.

Redirect STDIN
Several times, I find myself hitting my up arrow, and changing the search term. Unfortunately, I find myself wasting too much time typing: $ grep kernel /var/log/messages Redirecting STDIN allows me to put the search term at the end so I less cursor movement to change what I'm searching for: $ < /var/log/messages grep kernel If you're using the emacs keyboard binding, then after you press your up arrow, press CTRL+w to erase the word. If this has already been submitted, I couldn't find it with the search utility.

Generate Random Passwords
If you want a password length longer than 6, changing the -c6 to read -c8 will give you 8 random characters instead of 6. To end up with a line-feed, use this with echo: # echo `< /dev/urandom tr -dc _A-Z-a-z-0-9 | head -c6` Modern systems need higher strenght, so add some special characters: # < /dev/urandom tr -dc '12345!@#$%qwertQWERTasdfgASDFGzxcvbZXCVB' | head -c8

Calculate pi with specific scale
a() function in bc is for arctangent, available if using -l option included.

Reset hosed terminal,
stty sane resets the tty to basic usable function. The ^J is a newline -- sometimes CR/LF interpretation is broken so use the ^J explicitly.

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" }

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" }

Short and sweet output from dig(1)
Turn off almost all of dig's output except for what you'd see in a zone file. This can also be put into ~/.digrc.

watch iptables counters
Watch the number of packets/bytes coming through the firewall. Useful in setting up new iptables rules or chains. Use this output to reorder rules for efficiency.

journalctl -f
a tail -f variant of systemd journal. Follow the most recent updates or if events are appended to the journal


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