Commands using perl sorted by votes

Commands using perl (369)

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Replace DOS character ^M with newline using perl inline replace.

Replace DOS character ^M with newline using perl inline replace.
This is sample output - yours may be different.
-1

perl -pi -e "s/\r/\n/g" <file>

din7 · 2010-07-29 16:07:36 4
calculate in commandline with perl
This is sample output - yours may be different.
-1

perl -e 'print 1+1 ."\n";'

stubby · 2010-08-08 23:19:10 3
Perl One Liner to Generate a Random IP Address

Show Sample Output
This is sample output - yours may be different.
```
108.134.80.236
```
-1

perl -e 'printf "%vd\n",pack "N",rand 256**4'

seungwon · 2011-01-18 06:10:18 3
Print just line 4 from a textfile

Perl version - just for completeness sake ;)
This is sample output - yours may be different.
-1

perl -ne '$. == 4 && print && exit'

bashrc · 2011-09-05 21:52:16 3
Remove color codes (special characters) with perl

Removes special characters (colors) in '^]]Xm' and '^]]X;Ym' format from file. Use pipe ('input | perl [...]') or stream ('perl [...] You can use 'cat -v infile' as 'input' to show special characters instead of interpreting (there is problem with non-ASCII chars, they are replaced by M-[char]).
This is sample output - yours may be different.
-1

perl -ne 's/\^.{1,7}?m//g;print'

Tracerneo · 2012-01-02 01:32:33 6
Remove a line from a file using sed (useful for updating known SSH server keys when they change)

Easily removes line #2 in ~/.ssh/known_hosts. Show Sample Output
This is sample output - yours may be different.
-1

perl -p -i -e 's/.*\n//g if $.==2' ~/.ssh/known_hosts

meappy · 2012-01-17 14:11:03 3
Generate Random Text based on Length

If you don't have seq, you can use perl.
This is sample output - yours may be different.
-1

genRandomText() { perl -e '$n=shift; print chr(int(rand(26)) + 97) for 1..$n; print "\n"' $1;}

putnamhill · 2012-01-21 00:21:20 3
Per country GET report, based on access log. Easy to transform to unique IP

Per country GET report, based on access log. Easy to transform to unique IP Show Sample Output
This is sample output - yours may be different.
```
     71 , Poland
    116 , France
    300 , United States
   2426 , Spain
```
-1

cat /var/log/nginx/access.log | grep -oe '^[0-9.]\+' | perl -ne 'system("geoiplookup $_")' | grep -v found | grep -oe ', [A-Za-z ]\+$' | sort | uniq -c | sort -n

theist · 2012-05-08 13:28:25 3
Print environment information.

Show Sample Output
This is sample output - yours may be different.
```
user@server:~$ perl -e 'print "$_=$ENV{$_}\n" for keys %ENV'
HOME=/home/user
LESS=-R
LC_ALL=de_DE.utf8
EDITOR=/usr/bin/vim
...
```
-1

perl -e 'print "$_=$ENV{$_}\n" for keys %ENV'

sgikas · 2012-11-12 13:14:28 4
Find out if a module is installed in perl

Will check if the given module is installed in the @INC. It will print the path and return 0 if found, or 1 otherwise. Based on script from SharpyWarpy in http://www.linuxquestions.org/questions/linux-general-1/how-to-list-all-installed-perl-modules-216603/ Show Sample Output
This is sample output - yours may be different.
```
/usr/local/share/perl5/Collectd/Plugins/Graphite.pm
```
-1

perl -MFile::Find=find -MFile::Spec::Functions -Tlwe '$found=1; find { wanted => sub { if (/$ARGV[0]\.pm\z/) { print canonpath $_; $found=0; } }, no_chdir => 1 }, @INC; exit $found;' Collectd/Plugins/Graphite

keymon · 2013-01-11 11:01:46 5

Find out if a module is installed in perl (and what version)

This attempts to load a Perl Module (-M flag) and use version 9999, since no module has a version this high, Perl exits either a) telling you the version of the module installed or b) tells you it can't find the module. Show Sample Output

-1

perl -MModule::Name\ 9999 -e 1

three18ti · 2013-01-15 22:51:39 4

Display Spinner while waiting for some process to finish

Replace 'sleep 10' with the command to wait for Show Sample Output
This is sample output - yours may be different.
```
\oOooo
```
-1

sleep 10 & perl -e '$|=@s=qw(-Ooooo \oOooo |ooOoo /oooOo -ooooO \oooOo |ooOoo /oOooo);while(kill 0,'$!'){ print "\r",$s[$t++%($#s+1)];select(undef,undef,undef,0.2);}'

unixmonkey74668 · 2015-05-09 10:00:35 9
shell function to create an 'invisible regex' that won't show up when grepping the output from 'ps'

Note that `grep "$(ir foo)"` really doesn't save any typing, but wrapping this inside a second shell function will: psg() { grep "$(ir \"$@\")" ;} Show Sample Output
This is sample output - yours may be different.
```
$ ir foo
[f]oo

$ ps aux | grep "$(ir foo)"
[returns nothing]
```
-1

ir() { perl -pne 's/(.)(.*)/\[\1]\2/' <<< "$@" ;}

bartonski · 2015-07-25 14:13:33 12
rename all images in folder with original date time from exif data

for filename multilingual (ex.japanese, chinese, ...etc)
This is sample output - yours may be different.
-1

c=1; for i in *; do identify -verbose $i | perl -ane 'if(/exif:DateTimeOriginal:/){print "@F[1,2] "}'; ls -i $i; done | sort | perl -ane 'print "@F[2]\n"' | while read j; do find -inum $j | xargs -iX cp X NEW_`printf %02d $c`.jpg; cnt=`expr $c + 1`; done

huzioka · 2015-09-22 19:06:43 11
Binary digits Matrix effect
This is sample output - yours may be different.
-1

perl -e 'use Term::ANSIColor;$|++; while (1) { print color("green")," " x (rand(35) + 1), int(rand(2)), color("reset") }'

mvrpl · 2017-04-26 14:05:48 20
Inserting a decimal every third digit

self explanatory see sample output Show Sample Output
This is sample output - yours may be different.
```
# echo "1234435324523443212343241" | perl -lpe'1 while s/^([-+]?\d+)(\d{3})/$1.$2/'
1.234.435.324.523.443.212.343.241
```
-2

perl -lpe'1 while s/^([-+]?\d+)(\d{3})/$1.$2/'

sil · 2009-02-18 21:54:22 6
Convert files with CR-terminated lines (as created by Mac OS X programs) into NL-terminated lines suitable for Unix programs

Many Mac OS X programs, especially those in Microsoft:Office, create ASCII files with lines terminated by CRs (carriage returns). Most Unix programs expect lines separated by NLs (newlines). This little command makes it trivial to convert them. Show Sample Output
This is sample output - yours may be different.
```
crtonl mymacfile.csv
```
-2

function crtonl { perl -i -ape 's/\r\n?/\n/g;' $* ; }

totoro · 2009-03-25 20:28:32 10
Not so simple countdown from a given date

An improved version of http://www.commandlinefu.com/commands/view/1772/simple-countdown-from-a-given-date that uses Perl to pretty-print the output. Note that the GNU-style '--no-title' option has been replaced by its one-letter counterpart '-t'. Show Sample Output
This is sample output - yours may be different.
```
4d 23:15:43
```
-2

watch -tn1 'bc<<<"`date -d'\''friday 21:00'\'' +%s`-`date +%s`"|perl -ne'\''@p=gmtime($_);printf("%dd %02d:%02d:%02d\n",@p[7,2,1,0]);'\'

penpen · 2009-03-29 19:53:36 8
Read just the IP address of a device

Found this useful for scripts where I needed to work with the machine's IP. If $DEVICE is not specified, this will return all IPs on the machine. If $DEVICE is set to a network adapter, it will return just that adapter's IP.
This is sample output - yours may be different.
-2

ifconfig $DEVICE | perl -lne '/inet addr:([\d.]+)/ and print $1'

jdob · 2009-07-21 13:48:19 6
Make perl crash

It is not easy to make perl give a segfault, but this does it. This is a known issue but apparently not easy to fix. This is completely useless except for showing people that perl is not bullet-proof. Show Sample Output
This is sample output - yours may be different.
```
Segmentation fault
```
-2

perl -e '$x = []; push @$x, eval { $x = 1; return $x = 1; }'

dstahlke · 2009-10-07 22:42:18 8
Transforms a file to all uppercase.

same, except it works on any OS with Perl installed. DOS, Windose, whatever
This is sample output - yours may be different.
-2

perl -pi -e 's/([[:lower:]]+)/uc $1/gsex' file

linuxrawkstar · 2009-10-08 14:18:50 3
Echo several blank lines

Perl variant of echo several blank lines command
This is sample output - yours may be different.
-2

perl -e 'print "\n"x100'

SunX · 2010-09-07 10:11:10 3
Bulk install

I used this to mass install a lot of perl stuff. Threw it together because I was feeling *especially* lazy. The 'perl' and the 'module' can be replaced with whatever you like.
This is sample output - yours may be different.
-2

apt-cache search perl | grep module | awk '{print $1;}' | xargs sudo apt-get install -y

captwheeto · 2010-11-26 14:00:39 3
Get DELL Warranty Information from support.dell.com

The dates in the output are Start Date, End Date, Days Remaining in warranty, respectively. This will only work if you are running it on a dell machine. You can substitute the dmidecode command with a service tag if you are not using a dell. Also, you have to either allow your user to run sudo dmidecode with no password or run this command as root. Show Sample Output
This is sample output - yours may be different.
```
Product Support for Latitude D820

Your Warranty
Next Business Day Support 4/16/2008 4/16/2010 0
```
-2

curl -Ls "http://support.dell.com/support/DPP/Index.aspx?c=us&cs=08W&l=en&s=biz&ServiceTag=$(dmidecode -s system-serial-number)"|egrep -i '>Your Warranty<|>Product Support for'|html2text -style pretty|egrep -v 'Request|View'|perl -pane 's/^(\s+|\})//g;'

din7 · 2011-02-18 22:29:05 3
Print sorted list of all installed packages (Debian)

A space-padded version: perl -m'AptPkg::Cache' -e '$c=AptPkg::Cache->new; for (keys %$c){ push @a, $_ if $c->{$_}->{'CurrentState'} eq 'Installed';} print "$_ " for sort @a;'
This is sample output - yours may be different.
-2

perl -m'AptPkg::Cache' -le '$c=AptPkg::Cache->new; for (keys %$c){ push @a, $_ if $c->{$_}->{'CurrentState'} eq 'Installed';} print for sort @a;'

dbbolton · 2011-03-14 23:56:43 3
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ssh batch jobs: query hundreds of hosts with an ssh command

Need to query hundreds of hosts with an ssh command ? Of course you'll have setup keys on all your remote HOSTs. But in the case a key is not present this command will skip that node, proceeding on to the next. -t: Force pseudo-tty allocation. This can be used to execute arbitrary screen-based programs on a remote machine. Also prevents unwanted stty messages being sent to console -q: Quiet mode. -o "BatchMode yes" If set to yes, passphrase/password querying will be disabled. This option is useful in scripts and other batch jobs where no user is present

Find usb device in realtime

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

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.

Speak & Spell-esque glitch sounds

The Speak & Spell's sound chip uses a compressed audio format called "linear predictive coding". This command will read random bytes and attempt to decompress them as if it were audio data compressed in this format, then play it. This results in a unique sound which is similar to a glitching Speak & Spell.

Get all files of particular type (say, PDF) listed on some wegpage (say, example.com)

See man wget if you want linked files and not only those hosted on the website.

List the binaries installed by a Debian package

GNU grep's perl-compatible regular expression(PCRE).

make, or run a script, everytime a file in a directory is modified

df output, sorted by Use% and correctly maintaining header row

Show disk space info, grepping out the uninteresting ones beginning with ^none while we're at it. The main point of this submission is the way it maintains the header row with the command grouping, by removing it from the pipeline before it gets fed into the sort command. (I'm surprised sort doesn't have an option to skip a header row, actually..) It took me a while to work out how to do this, I thought of it as I was drifting off to sleep last night!

Pause and Resume Processes

Add that and "cont () { ps -ec | grep $@ | kill -SIGCONT `awk '{print $1}'`; }" (without the quotes) to you bash profile and then use it to pause and resume processes safely

Print Memory Utilization Percentage For a specific process and it's children

Change the name of the process and what is echoed to suit your needs. The brackets around the h in the grep statement cause grep to skip over "grep httpd", it is the equivalent of grep -v grep although more elegant.

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Commands using perl (369)

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