Commands using perl (369)
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This is from perldoc -q random.*line, which says: This has a significant advantage in space over reading the whole file in. You can find a proof of this method in The Art of Computer Programming, Volume 2, Section 3.4.2, by Donald E. Knuth. Who am I to argue with Don Knuth?
1perl -e 'rand($.) < 1 && ($line = $_) while <>;' -
Can also just use the debug mode like this. Show Sample Output
1perl -dwe 1 -
Replace PACKAGE with desired package name. Found here: http://mikebeach.org/2011/04/undo-apt-get-build-dep/
1sudo aptitude markauto $(apt-cache showsrc PACKAGE | grep Build-Depends | perl -p -e 's/(?:[\[(].+?[\])]|Build-Depends:|,|\|)//g') -
Recursively delete empty directories. Use with care.
1perl -MFile::Find -e"finddepth(sub{rmdir},'.')" -
1arp-scan -I eth0 -l | perl -ne '/((\d{1,3}\.){3}\d{1,3})/ and $ip=$1 and $_=`nmblookup -A $ip` and /([[:alnum:]-]+)\s+<00>[^<]+<ACTIVE>/m and printf "%15s %s\n",$ip,$1'
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1perl -mText::Highlight -E 'say Text::Highlight->new(ansi => 1)->highlight(Perl => do { local (@ARGV,$/) = shift; <> }) ' path/to/perl-file.pl
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this command example converts to 25 fps subtitles that were originally created for 24 fps movie
1cat subtitles.txt | perl -pe 's/} /}/g; s/{(\d+)}/=1=/; $f1=(24/25*$1); s/{(\d+)}/=2=/; $f2=(24/25*$1); $f1=~s/\..*//; $f2=~s/\..*//; s/=1=/{$f1}/; s/=2=/{$f2}/; ' > subtitles_newfps.txt -
Calls the POSIX strerror() function to look up the meaning of integer ERRNOs set by some functions.
1perl -MPOSIX -e 'print strerror($ARGV[0])."\n";' ERRNO -
from http://stackoverflow.com/questions/1030787/multiline-search-replace-with-perl added greedy trick in wildcard match (.*?) from http://www.troubleshooters.com/codecorn/littperl/perlreg.htm#Greedy Show Sample Output
1perl -i -pe 'BEGIN{undef $/;} s/START.*?STOP/replace_string/smg' file_to_change -
the output of svn log is annoying to grep, since it spreads the useful info over multiple lines. This compacts the output down to one line so eg you can grep for a comment and see the rev, date & committer straight away. Updated: MUCH shorter, easier to remember. Now it just replaces newlines with spaces, except on '---' lines. Show Sample Output
1svn log | perl -l40pe 's/^-+/\n/' -
1perl -ane 'END{printf(" %d %d %d\n", $x, $y, $z)} $x+=1; $y+=@F; $z+=length' file.txt
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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)
1useradd -m -p $(perl -e'print crypt("passwordscelta", "stigghiola")') user -
This one line Perl script will display the smallest to the largest files sizes in all directories on a server. Show Sample Output
1du -k | sort -n | perl -ne 'if ( /^(\d+)\s+(.*$)/){$l=log($1+.1);$m=int($l/log(1024)); printf ("%6.1f\t%s\t%25s %s\n",($1/(2**(10*$m))),(("K","M","G","T","P")[$m]),"*"x (1.5*$l),$2);}' | more -
Requires perl 5.14 or greater
1perl -e 'rename $_, s/ /-/gr for <*.mp3>' -
This prints file access rights in octal - useful when "stat" is unavailable. Show Sample Output
1perl -e 'printf "%04o\n", (stat shift)[2] & 0777;' file -
extract data in multiline blocks of data with perl pattern matching loop Show Sample Output
1cat z.log | perl -ne 'BEGIN{ print "DATE;RATE\n"; } /\[(\d.*)\]/ && print $1; /CURRENT RATE: +(\S+) msg.*/ && print ";" .$1 . "\n"; ' -
1perl -e 'printf "00:16:3E:%02X:%02X:%02X\n", rand 0xFF, rand 0xFF, rand 0xFF'
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Really helpfull when play with files having spaces an other bad name. Easy to store and access names and path in just a field while saving it in a file. This format (URL) is directly supported by nautilus and firefox (and other browsers) Show Sample Output
1convert_path2uri () { echo -n 'file://'; echo -n "$1" | perl -pe 's/([^a-zA-Z0-9_\/.])/sprintf("%%%.2x", ord($1))/eg' ;} #convert2uri '/tmp/a b' ### convert file path to URI -
Sets the @ A record for your domain hosted by namecheap to your current internet-facing IP address, logs success or failure with syslog, and logs the data returned to /root/dnsupdate. Change the XXX's as appropriate. More info at: http://www.namecheap.com/support/knowledgebase/article.aspx/29/ Show Sample Output
1logger -tdnsupdate $(curl -s 'https://dynamicdns.park-your-domain.com/update?host=@&domain=xxx&password=xxx'|tee -a /root/dnsupdate|perl -pe'/Count>(\d+)<\/Err/;$_=$1eq"0"?"Update Sucessful":"Update failed"'&&date>>/root/dnsupdate) -
Use it to send raw data to a networked device. Used to interact with relay controller board whose documentation is lost, so use wireshark to sniff the sent data and replayed using the command.
1echo -n 023135 | perl -pe 's/([0-9a-f]{2})/chr hex $1/gie' | nc -4u -q1 -p5001 192.168.0.100 2000 -
Converts control codes and spaces (ASCII code ≤ 32) to visible Unicode Control Pictures, U+2400 ? U+2420. Skips \n characters, which is probably a good thing. Show Sample Output
1/bin/echo -e '\002Hello, Folks\t!\r' | perl -pwle 'use v5.14; s/([\N{U+0000}-\N{U+0020}])/chr(9216+ord($1))/ge;' -
An advantage is that this doesn't modify remained string at all. One can change {0,1} with {0,n} to drop several columns
1perl -pE's/(\S+\s*){0,1}//' -
Better than the others, and actually works unlike some of them. Show Sample Output
1objdump -d $1 | grep -Po '\s\K[a-f0-9]{2}(?=\s)' | sed 's/^/\\x/g' | perl -pe 's/\r?\n//' | sed 's/$/\n/' -
Based on http://stackoverflow.com/questions/13127352/checking-alternative-names-for-a-san-ssl-cert Replace "facebook.com" with the desired hostname. Show Sample Output
1echo "quit" | openssl s_client -connect facebook.com:443 | openssl x509 -noout -text | grep "DNS:" | perl -pe "s/(, )?DNS:/\n/g" -
1find . -type f | perl -ne 'print $1 if m/\.([^.\/]+)$/' | sort -u
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