Generate a random character password
perl -le 'print map { ("a".."z")[rand 26] } 1..8'
Create a string of specific length
perl -le 'print "a"x50'
Create a repeated list of elements
perl -le '@list = (1,2)x20; print "@list"'
Create a string from an array
perl -le "@stuff = ("hello", 0..9, "world"); print join '-', @stuff"
Find the numeric values for characters in the string
perl -le 'print join ", ", map { ord } split //, "hello world"'
Convert a list of numeric ASCII values into a string
perl -le '@ascii = (99, 111, 100, 105, 110, 103); print pack("C*", @ascii)'
perl -le '@ascii = (99, 111, 100, 105, 110, 103); print map { chr } @ascii'
Generate an array with odd numbers from 1 to 100
perl -le '@odd = grep {$_ % 2 == 1} 1..100; print "@odd"'
Generate an array with even numbers from 1 to 100
perl -le '@even = grep {$_ % 2 == 0} 1..100; print "@even"'
Find the length of the string
perl -le 'print length "one-liners are great"'
Find the number of elements in an array
perl -le '@array = ("a".."z"); print scalar @array'
perl -le '@array = ("a".."z"); print $#array + 1'
Perl one-liner to get the current week number
perl -e 'use Date::Calc qw(Today Week_Number); $weekn = Week_Number(Today); print "$weekn\n"'
Pick a random line from a file
perl -e 'rand($.) < 1 && ($line = $_) while <>;'
Print a list of standard error codes and descriptions.
perl -le 'print $!+0, "\t", $!++ for 0..127'
Rearrange words from a file
perl -lane 'print "$F[0]:$F[1]:$F[2]"' myfile
Recursive Search and Replace
perl -pi -e's/WHAT TO FIND/WHAT TO REPLACE IT WITH/g' $(grep -Rl WHAT TO FIND /DIR/*)
Remove duplicate rows of an un-sorted file based on a single column
perl -ane 'print unless $x{$F[0]}++' infile > outfile
Replace all environment variable references in files with environemnt variable values
perl -p -e 's/\$(\w+)/$ENV{$1}/g;' FILES...
Show full path followed by a command
perl -le 'chomp($w=$(which $ARGV[0]));$_=$(file $w);while(/link\b/){chomp($_=(split/''/,$_)[1]);chop$_;$w.=" -> $_";$_=''file $_`;}print "\n$w";' COMMAND_NAME
Show which include directories your installation of Perl is using.
perl -le 'print join $/, @INC'
Sum column 1
perl -alne 'END{print $a} $a+=$F[0]' <inputfile
Check if a number is a prime
perl -lne '(1x$_) !~ /^1?$|^(11+?)\1+$/ && print "$_ is prime"'
Print the sum of all the fields on a line
perl -MList::Util=sum -alne 'print sum @F'
Print the sum of all the fields on all lines
perl -MList::Util=sum -alne 'push @S,@F; END { print sum @S }'
perl -MList::Util=sum -alne '$s += sum @F; END { print $s }'
Shuffle all fields on a line
perl -MList::Util=shuffle -alne 'print "@{[shuffle @F]}"'
perl -MList::Util=shuffle -alne 'print join " ", shuffle @F'
Find the minimum element on a line
perl -MList::Util=min -alne 'print min @F'
Find the minimum element over all the lines
perl -MList::Util=min -alne '@M = (@M, @F); END { print min @M }'
perl -MList::Util=min -alne '$min = min @F; $rmin = $min unless defined $rmin && $min > $rmin; END { print $rmin }'
Find the maximum element on a line
perl -MList::Util=max -alne 'print max @F'
Find the maximum element over all the lines
perl -MList::Util=max -alne '@M = (@M, @F); END { print max @M }'
Replace each field with its absolute value
perl -alne 'print "@{[map { abs } @F]}"'
Find the total number of fields (words) on each line
perl -alne 'print scalar @F'
Print the total number of fields (words) on each line followed by the line
perl -alne 'print scalar @F, " $_"'
Find the total number of fields (words) on all lines
perl -alne '$t += @F; END { print $t}'
Print the total number of fields that match a pattern
perl -alne 'map { /regex/ && $t++ } @F; END { print $t }'
perl -alne '$t += /regex/ for @F; END { print $t }'
perl -alne '$t += grep /regex/, @F; END { print $t }'
Print the total number of lines that match a pattern
perl -lne '/regex/ && $t++; END { print $t }'
Generate 10 random numbers between 5 and 15 (excluding 15)
perl -le '$n=10; $min=5; $max=15; $, = " "; print map { int(rand($max-$min))+$min } 1..$n'
Convert an IP address to unsigned integer
perl -le '$i=3; $u += ($_<<8*$i--) for "127.0.0.1" =~ /(\d+)/g; print $u'
perl -le '$ip="127.0.0.1"; $ip =~ s/(\d+)\.?/sprintf("%02x", $1)/ge; print hex($ip)'
perl -le 'print unpack("N", 127.0.0.1)'
perl -MSocket -le 'print unpack("N", inet_aton("127.0.0.1"))'
Convert an unsigned integer to an IP address
perl -MSocket -le 'print inet_ntoa(pack("N", 2130706433))'
perl -le '$ip = 2130706433; print join ".", map { (($ip>>8*($_))&0xFF) } reverse 0..3'
perl -le '$ip = 2130706433; $, = "."; print map { (($ip>>8*($_))&0xFF) } reverse 0..3'
Convert a decimal number to hex using @hex lookup table
perl -le '$num = 255; @hex = (0..9, "a".."f"); while ($num) { $s = $hex[($num%16)&15].$s; $num = int $num/16 } print $s'
perl -le '$hex = sprintf("%x", 255); print $hex'
perl -le '$num = "ff"; print hex $num'
N-space a file
perl -pe '$_.="\n"x7'
Remove all blank lines
perl -ne 'print unless /^$/' perl -lne 'print if length' perl -ne 'print if /\S/'
Remove all consecutive blank lines, leaving just one
perl -00 -pe '' perl -00pe0
Number only non-empty lines in a file
perl -pe '$_ = ++$a." $_" if /./'
Number and print only non-empty lines in a file (drop empty lines)
perl -ne 'print ++$a." $_" if /./'
Print the number of lines in a file that match a pattern (emulate grep
perl -lne '$a++ if /regex/; END {print $a+0}'
perl -nE '$a++ if /regex/; END {say $a+0}'
Reverse a file
perl -e'@f=<>;print reverse@f' file
ROT 13 a file
perl -lpe 'y/A-Za-z/N-ZA-Mn-za-m/' file
Base64 encode a string
perl -MMIME::Base64 -e 'print encode_base64("string")'
perl -MMIME::Base64 -0777 -ne 'print encode_base64($_)' file
Base64 decode a string
perl -MMIME::Base64 -le 'print decode_base64("base64string")'
perl -MMIME::Base64 -ne 'print decode_base64($_)' file
URL-escape a string
perl -MURI::Escape -le 'print uri_escape($string)'
URL-unescape a string
perl -MURI::Escape -le 'print uri_unescape($string)'
HTML-encode a string
perl -MHTML::Entities -le 'print encode_entities($string)'
HTML-decode a string
perl -MHTML::Entities -le 'print decode_entities($string)'
Convert all text to uppercase
perl -nle 'print uc' perl -ple '$_=uc' perl -nle 'print "\U$_"'
Convert all text to lowercase
perl -nle 'print lc' perl -ple '$_=lc' perl -nle 'print "\L$_"'
Uppercase only the first word of each line
perl -nle 'print ucfirst lc' perl -nle 'print "\u\L$_"'
Invert the letter case
perl -ple 'y/A-Za-z/a-zA-Z/'
Camel case each line
perl -ple 's/(\w+)/\u$1/g' perl -ple "s/(?<!['])(\w+)/\u\1/g"
Strip leading whitespace (spaces, tabs) from the beginning of each line
perl -ple 's/^[ \t]+//' perl -ple 's/^\s+//'
Strip trailing whitespace (space, tabs) from the end of each line
perl -ple 's/[ \t]+$//'
Strip whitespace from the beginning and end of each line
perl -ple 's/^[ \t]+|[ \t]+$//g'
Convert UNIX newlines to DOS/Windows newlines
perl -pe 's|\n|\r\n|'
Convert DOS/Windows newlines to UNIX newlines
perl -pe 's|\r\n|\n|'
Convert UNIX newlines to Mac newlines
perl -pe 's|\n|\r|'
Substitute (find and replace) “foo” with “bar” on each line
perl -pe 's/foo/bar/'
Substitute (find and replace) all “foo”s with “bar” on each line
perl -pe 's/foo/bar/g'
Substitute (find and replace) “foo” with “bar” on lines that match “baz”
perl -pe '/baz/ && s/foo/bar/'
Binary patch a file (find and replace a given array of bytes as hex numbers)
perl -pi -e 's/\x89\xD8\x48\x8B/\x90\x90\x48\x8B/g' file
print the first line of a file (emulate head -1)
perl -ne 'print; exit'
print the first 10 lines of a file (emulate head -10)
perl -ne 'print if $. <= 10' perl -ne '$. <= 10 && print' perl -ne 'print if 1..10'
print the last line of a file (emulate tail -1)
perl -ne '$last = $_; end { print $last }'
perl -ne 'print if eof'
print the last 10 lines of a file (emulate tail -10)
perl -ne 'push @a, $_; @a = @a[@a-10..$#a]; end { print @a }'
print only lines that match a regular expression
perl -ne '/regex/ && print'
print only lines that do not match a regular expression
perl -ne '!/regex/ && print'
print the line before a line that matches a regular expression
perl -ne '/regex/ && $last && print $last; $last = $_'
print the line after a line that matches a regular expression
perl -ne 'if ($p) { print; $p = 0 } $p++ if /regex/'
print all lines between two regexes (including lines that match regex)
perl -ne 'print if /regex1/../regex2/'
print all lines from line 17 to line 30
perl -ne 'print if $. >= 17 && $. <= 30'
perl -ne 'print if int($.) ~~ (17..30)'
perl -ne 'print if grep { $_ == $. } 17..30'
print all lines that contain only characters
perl -ne 'print if /^[[:alpha:]]+$/'
print all unique lines
perl -ne 'print unless $a{$_}++'
print the first field (word) of every line (emulate cut -f 1 -d ’ ’)
perl -alne 'print $f[0]'