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1=head1 NAME
2
3perlcheat - Perl 5 Cheat Sheet
4
5=head1 DESCRIPTION
6
7This 'cheat sheet' is a handy reference, meant for beginning Perl
b3631f69 8programmers. Not everything is mentioned, but 195 features may
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9already be overwhelming.
10
11=head2 The sheet
12
13 CONTEXTS SIGILS ARRAYS HASHES
14 void $scalar whole: @array %hash
15 scalar @array slice: @array[0, 2] @hash{'a', 'b'}
16 list %hash element: $array[0] $hash{'a'}
17 &sub
18 *glob SCALAR VALUES
19 number, string, reference, glob, undef
20 REFERENCES
21 \ references $$foo[1] aka $foo->[1]
22 $@%&* dereference $$foo{bar} aka $foo->{bar}
23 [] anon. arrayref ${$$foo[1]}[2] aka $foo->[1]->[2]
24 {} anon. hashref ${$$foo[1]}[2] aka $foo->[1][2]
25 \() list of refs
26 NUMBERS vs STRINGS LINKS
27 OPERATOR PRECEDENCE = = perl.plover.com
28 -> + . search.cpan.org
29 ++ -- == != eq ne cpan.org
30 ** < > <= >= lt gt le ge pm.org
31 ! ~ \ u+ u- <=> cmp tpj.com
32 =~ !~ perldoc.com
33 * / % x SYNTAX
34 + - . for (LIST) { }, for (a;b;c) { }
35 << >> while ( ) { }, until ( ) { }
36 named uops if ( ) { } elsif ( ) { } else { }
37 < > <= >= lt gt le ge unless ( ) { } elsif ( ) { } else { }
38 == != <=> eq ne cmp for equals foreach (ALWAYS)
39 &
40 | ^ REGEX METACHARS REGEX MODIFIERS
41 && ^ string begin /i case insens.
42 || $ str. end (before \n) /m line based ^$
43 .. ... + one or more /s . includes \n
44 ?: * zero or more /x ign. wh.space
45 = += -= *= etc. ? zero or one /g global
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46 , => {3,7} repeat in range /o cmpl pat. once
47 list ops () capture
48 not (?:) no capture REGEX CHARCLASSES
49 and [] character class . == [^\n]
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50 or xor | alternation \s == whitespace
51 \b word boundary \w == word characters
52 \z string end \d == digits
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53 DO \S, \W and \D negate
54 use strict; DON'T
55 use warnings; "$foo" LINKS
56 my $var; $$variable_name perl.com
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57 open() or die $!; `$userinput` use.perl.org
58 use Modules; /$userinput/ perl.apache.org
b3631f69 59
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60 FUNCTION RETURN LISTS
61 stat localtime caller SPECIAL VARIABLES
62 0 dev 0 second 0 package $_ default variable
63 1 ino 1 minute 1 filename $0 program name
64 2 mode 2 hour 2 line $/ input separator
65 3 nlink 3 day 3 subroutine $\ output separator
66 4 uid 4 month-1 4 hasargs $| autoflush
67 5 gid 5 year-1900 5 wantarray $! sys/libcall error
68 6 rdev 6 weekday 6 evaltext $@ eval error
69 7 size 7 yearday 7 is_require $$ process ID
70 8 atime 8 is_dst 8 hints $. line number
71 9 mtime 9 bitmask @ARGV command line args
72 10 ctime just use @INC include paths
73 11 blksz POSIX:: 3..9 only @_ subroutine args
74 12 blcks strftime! with EXPR %ENV environment
75
76=head1 ACKNOWLEDGEMENTS
77
78The first version of this document appeared on Perl Monks, where several
79people had useful suggestions. Thank you, Perl Monks.
80
81A special thanks to Damian Conway, who didn't only suggest important changes,
82but also took the time to count the number of listed features and make a
83Perl 6 version to show that Perl will stay Perl.
84
85=head1 AUTHOR
86
740d4bb2 87Juerd Waalboer <#####@juerd.nl>, with the help of many Perl Monks.
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88
89=head1 SEE ALSO
90
91 http://perlmonks.org/?node_id=216602 the original PM post
92 http://perlmonks.org/?node_id=238031 Damian Conway's Perl 6 version
93 http://juerd.nl/site.plp/perlcheat home of the Perl Cheat Sheet