1PERLCHEAT(1) Perl Programmers Reference Guide PERLCHEAT(1)
2
6 perlcheat - Perl 5 Cheat Sheet
7
9 This 'cheat sheet' is a handy reference, meant for beginning Perl
10 programmers. Not everything is mentioned, but 195 features may already
11 be overwhelming.
12 The sheet
14 CONTEXTS SIGILS ARRAYS HASHES
15 void $scalar whole: @array %hash
16 scalar @array slice: @array[0, 2] @hash{'a', 'b'}
17 list %hash element: $array[0] $hash{'a'}
18 &sub
19 *glob SCALAR VALUES
20 number, string, reference, glob, undef
21 REFERENCES
22 \ references $$foo[1] aka $foo->[1]
23 $@%&* dereference $$foo{bar} aka $foo->{bar}
24 [] anon. arrayref ${$$foo[1]}[2] aka $foo->[1]->[2]
25 {} anon. hashref ${$$foo[1]}[2] aka $foo->[1][2]
26 \() list of refs
27 NUMBERS vs STRINGS LINKS
28 OPERATOR PRECEDENCE = = perl.plover.com
29 -> + . search.cpan.org
30 ++ -- == != eq ne cpan.org
31 ** < > <= >= lt gt le ge pm.org
32 ! ~ \ u+ u- <=> cmp tpj.com
33 =~ !~ perldoc.com
34 * / % x SYNTAX
35 + - . for (LIST) { }, for (a;b;c) { }
36 << >> while ( ) { }, until ( ) { }
37 named uops if ( ) { } elsif ( ) { } else { }
38 < > <= >= lt gt le ge unless ( ) { } elsif ( ) { } else { }
39 == != <=> eq ne cmp ~~ for equals foreach (ALWAYS)
40 &
41 | ^ REGEX METACHARS REGEX MODIFIERS
42 && ^ string begin /i case insens.
43 || // $ str. end (before \n) /m line based ^$
44 .. ... + one or more /s . includes \n
45 ?: * zero or more /x ign. wh.space
46 = += -= *= etc. ? zero or one /g global
47 , => {3,7} repeat in range /o cmpl pat. once
48 list ops () capture
49 not (?:) no capture REGEX CHARCLASSES
50 and [] character class . == [^\n]
51 or xor | alternation \s == whitespace
52 \b word boundary \w == word characters
53 \z string end \d == digits
54 DO \S, \W and \D negate
55 use strict; DON'T
56 use warnings; "$foo" LINKS
57 my $var; $$variable_name perl.com
58 open() or die $!; `$userinput` use.perl.org
59 use Modules; /$userinput/ perl.apache.org
60 FUNCTION RETURN LISTS
62 stat localtime caller SPECIAL VARIABLES
63 0 dev 0 second 0 package $_ default variable
64 1 ino 1 minute 1 filename $0 program name
65 2 mode 2 hour 2 line $/ input separator
66 3 nlink 3 day 3 subroutine $\ output separator
67 4 uid 4 month-1 4 hasargs $| autoflush
68 5 gid 5 year-1900 5 wantarray $! sys/libcall error
69 6 rdev 6 weekday 6 evaltext $@ eval error
70 7 size 7 yearday 7 is_require $$ process ID
71 8 atime 8 is_dst 8 hints $. line number
72 9 mtime 9 bitmask @ARGV command line args
73 10 ctime just use @INC include paths
74 11 blksz POSIX:: 3..9 only @_ subroutine args
75 12 blcks strftime! with EXPR %ENV environment
76
78 The first version of this document appeared on Perl Monks, where
79 several people had useful suggestions. Thank you, Perl Monks.
80 A special thanks to Damian Conway, who didn't only suggest important
82 changes, but also took the time to count the number of listed features
83 and make a Perl 6 version to show that Perl will stay Perl.
84
86 Juerd Waalboer <#####@juerd.nl>, with the help of many Perl Monks.
87
89 http://perlmonks.org/?node_id=216602 the original PM post
90 http://perlmonks.org/?node_id=238031 Damian Conway's Perl 6 version
91 http://juerd.nl/site.plp/perlcheat home of the Perl Cheat Sheet
92perl v5.12.4 2011-06-07 PERLCHEAT(1)