Perl 5 Cheat Sheet by Arjen Laarhoven, based on Juerd Waalboer's cheat sheet Contexts Sigils Arrays Hashes Scalar values References Operator precedence Numbers/Strings Regex metacharacters Regex modifiers Regex character classes Function return lists Special variables Do Don't Links CONTEXTS void scalar list SIGILS $scalar @array %hash &sub *glob ARRAYS @array @array[0, 2] $array[0] HASHES %hash $hash{'a'} @hash{'a','b'} SCALAR VALUES number string reference glob undef REFERENCES \ reference $@%&* dereference [] anon arrayref {} anon hashref \() list of refs $$foo[1] => $foo->[1] $$foo{bar} => $foo->{bar} ${$$foo[1]}[2] => $foo->[1]->[2] ${$$foo[1]}[2] => $foo->[1][2] Operator Precedence -> ++ -- ** ! ~ / u+ u- =~ !~ * / % x + - . << >> named uops < > <= >= lt gt le ge == != <=> eq ne cmp & | ^ && || .. ... ?: = += -= *= etc. list ops not and or xor NUMBERS/STRINGS NUM STR = = + . == != eq ne < > <= >= lt gt le ge <=> cmp REGEX METACHARACTERS ^ string begin $ string end + one or more * zero or more ? zero or one {3,7} repeat in range () capture (?:) no capture [] character class | alternation \b word boundary \z string end REGEX MODIFIERS /i case insens. /m line based ^$ /s . includes \n /x ignore whitespace /g global REGEX CHARCLASSES . == [^\n] \s == [\x20\f\t\r\n] \w == [A-Za-z0-9_] \d == [0-9] \S, \W and \D negate FUNCTION RETURN LISTS stat localtime 0 dev 0 second 1 ino 1 minute 2 mode 2 hour 3 nlink 3 day 4 uid 4 mon-1 5 gid 5 yr-1900 6 rdev 6 wday 7 size 7 yrday 8 atime 8 is_dst 9 mtime 10 ctime 11 blksz 12 blcks caller 0 package 5 wantarray 1 filename 6 evaltext 2 line 7 is_require 3 subroutine 8 hints 4 hashargs 9 bitmask 0..9 only with EXPR SPECIAL VARIABLES $_ default variable $0 program name $/ input separator $\ output separator $| autoflush $! sys/libcall error $@ eval error $$ process ID $. line number @ARGV command line args @INC include paths @_ subroutine args %ENV environment DO use strict; use warnings; my $var; open() or die $!; use Modules; DON'T "$foo" $$variable_name `$userinput` /$userinput/ LINKS perl.plover.com search.cpan.org cpan.org pm.org tpj.com perldoc.com perl.com perlmonks.org use.perl.org perl.apache.org parrotcode.org