| 1 | =head1 NAME |
| 2 | |
| 3 | perlcheat - Perl 5 Cheat Sheet |
| 4 | |
| 5 | =head1 DESCRIPTION |
| 6 | |
| 7 | This 'cheat sheet' is a handy reference, meant for beginning Perl |
| 8 | programmers. Not everything is mentioned, but 195 features may |
| 9 | already 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 |
| 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] |
| 50 | or xor | alternation \s == whitespace |
| 51 | \b word boundary \w == word characters |
| 52 | \z string end \d == digits |
| 53 | DO \S, \W and \D negate |
| 54 | use strict; DON'T |
| 55 | use warnings; "$foo" LINKS |
| 56 | my $var; $$variable_name perl.com |
| 57 | open() or die $!; `$userinput` use.perl.org |
| 58 | use Modules; /$userinput/ perl.apache.org |
| 59 | |
| 60 | FUNCTION RETURN LISTS |
| 61 | stat localtime caller SPECIAL VARIABLES |
| 62 | 0 dev 0 second 0 package $_ default variable |
| 63 | 1 ino 1 minute 1 filename $0 program name |
| 64 | 2 mode 2 hour 2 line $/ input separator |
| 65 | 3 nlink 3 day 3 subroutine $\ output separator |
| 66 | 4 uid 4 month-1 4 hasargs $| autoflush |
| 67 | 5 gid 5 year-1900 5 wantarray $! sys/libcall error |
| 68 | 6 rdev 6 weekday 6 evaltext $@ eval error |
| 69 | 7 size 7 yearday 7 is_require $$ 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 | |
| 78 | The first version of this document appeared on Perl Monks, where several |
| 79 | people had useful suggestions. Thank you, Perl Monks. |
| 80 | |
| 81 | A special thanks to Damian Conway, who didn't only suggest important changes, |
| 82 | but also took the time to count the number of listed features and make a |
| 83 | Perl 6 version to show that Perl will stay Perl. |
| 84 | |
| 85 | =head1 AUTHOR |
| 86 | |
| 87 | Juerd Waalboer <#####@juerd.nl>, with the help of many Perl Monks. |
| 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 |