| 1 | =head1 NAME
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| 2 |
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| 3 | perlcheat - Perl 5 Cheat Sheet
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| 4 |
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| 5 | =head1 DESCRIPTION
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| 6 |
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| 7 | This 'cheat sheet' is a handy reference, meant for beginning Perl
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| 8 | programmers. Not everything is mentioned, but 194 features may
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| 9 | already be overwhelming.
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| 10 |
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| 11 | =head2 The sheet
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| 12 |
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| 13 | CONTEXTS SIGILS ARRAYS HASHES
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| 14 | void $scalar whole: @array %hash
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| 15 | scalar @array slice: @array[0, 2] @hash{'a', 'b'}
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| 16 | list %hash element: $array[0] $hash{'a'}
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| 17 | &sub
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| 18 | *glob SCALAR VALUES
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| 19 | number, string, reference, glob, undef
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| 20 | REFERENCES
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| 21 | \ references $$foo[1] aka $foo->[1]
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| 22 | $@%&* dereference $$foo{bar} aka $foo->{bar}
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| 23 | [] anon. arrayref ${$$foo[1]}[2] aka $foo->[1]->[2]
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| 24 | {} anon. hashref ${$$foo[1]}[2] aka $foo->[1][2]
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| 25 | \() list of refs
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| 26 | NUMBERS vs STRINGS LINKS
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| 27 | OPERATOR PRECEDENCE = = perl.plover.com
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| 28 | -> + . search.cpan.org
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| 29 | ++ -- == != eq ne cpan.org
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| 30 | ** < > <= >= lt gt le ge pm.org
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| 31 | ! ~ \ u+ u- <=> cmp tpj.com
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| 32 | =~ !~ perldoc.com
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| 33 | * / % x SYNTAX
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| 34 | + - . for (LIST) { }, for (a;b;c) { }
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| 35 | << >> while ( ) { }, until ( ) { }
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| 36 | named uops if ( ) { } elsif ( ) { } else { }
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| 37 | < > <= >= lt gt le ge unless ( ) { } elsif ( ) { } else { }
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| 38 | == != <=> eq ne cmp for equals foreach (ALWAYS)
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| 39 | &
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| 40 | | ^ REGEX METACHARS REGEX MODIFIERS
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| 41 | && ^ string begin /i case insens.
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| 42 | || $ str. end (before \n) /m line based ^$
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| 43 | .. ... + one or more /s . includes \n
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| 44 | ?: * zero or more /x ign. wh.space
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| 45 | = += -= *= etc. ? zero or one /g global
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| 46 | , => {3,7} repeat in range
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| 47 | list ops () capture REGEX CHARCLASSES
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| 48 | not (?:) no capture . == [^\n]
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| 49 | and [] character class \s == [\x20\f\t\r\n]
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| 50 | or xor | alternation \w == [A-Za-z0-9_]
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| 51 | \b word boundary \d == [0-9]
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| 52 | \z string end \S, \W and \D negate
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| 53 | DO
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| 54 | use strict; DON'T LINKS
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| 55 | use warnings; "$foo" perl.com
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| 56 | my $var; $$variable_name perlmonks.org
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| 57 | open() or die $!; `$userinput` use.perl.org
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| 58 | use Modules; /$userinput/ perl.apache.org
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| 59 | parrotcode.org
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| 60 | FUNCTION RETURN LISTS
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| 61 | stat localtime caller SPECIAL VARIABLES
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| 62 | 0 dev 0 second 0 package $_ default variable
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| 63 | 1 ino 1 minute 1 filename $0 program name
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| 64 | 2 mode 2 hour 2 line $/ input separator
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| 65 | 3 nlink 3 day 3 subroutine $\ output separator
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| 66 | 4 uid 4 month-1 4 hasargs $| autoflush
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| 67 | 5 gid 5 year-1900 5 wantarray $! sys/libcall error
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| 68 | 6 rdev 6 weekday 6 evaltext $@ eval error
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| 69 | 7 size 7 yearday 7 is_require $$ process ID
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| 70 | 8 atime 8 is_dst 8 hints $. line number
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| 71 | 9 mtime 9 bitmask @ARGV command line args
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| 72 | 10 ctime just use @INC include paths
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| 73 | 11 blksz POSIX:: 3..9 only @_ subroutine args
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| 74 | 12 blcks strftime! with EXPR %ENV environment
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| 75 |
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| 76 | =head1 ACKNOWLEDGEMENTS
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| 77 |
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| 78 | The first version of this document appeared on Perl Monks, where several
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| 79 | people had useful suggestions. Thank you, Perl Monks.
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| 80 |
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| 81 | A special thanks to Damian Conway, who didn't only suggest important changes,
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| 82 | but also took the time to count the number of listed features and make a
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| 83 | Perl 6 version to show that Perl will stay Perl.
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| 84 |
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| 85 | =head1 AUTHOR
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| 86 |
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| 87 | Juerd Waalboer <[email protected]>, with the help of many Perl Monks.
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| 88 |
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| 89 | =head1 SEE ALSO
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| 90 |
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| 91 | http://perlmonks.org/?node_id=216602 the original PM post
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| 92 | http://perlmonks.org/?node_id=238031 Damian Conway's Perl 6 version
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| 93 | http://juerd.nl/site.plp/perlcheat home of the Perl Cheat Sheet
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