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=head1 NAME perlcheat - Perl 5 Cheat Sheet =head1 DESCRIPTION This 'cheat sheet' is a handy reference, meant for beginning Perl programmers. Not everything is mentioned, but 195 features may already be overwhelming. =head2 The sheet CONTEXTS SIGILS ref ARRAYS HASHES void $scalar SCALAR @array %hash scalar @array ARRAY @array[0, 2] @hash{'a', 'b'} list %hash HASH $array[0] $hash{'a'} &sub CODE *glob GLOB SCALAR VALUES FORMAT number, string, ref, glob, undef REFERENCES \ reference $$foo[1] aka $foo->[1] $@%&* dereference $$foo{bar} aka $foo->{bar} [] anon. arrayref ${$$foo[1]}[2] aka $foo->[1]->[2] {} anon. hashref ${$$foo[1]}[2] aka $foo->[1][2] \() list of refs SYNTAX OPERATOR PRECEDENCE foreach (LIST) { } for (a;b;c) { } -> while (e) { } until (e) { } ++ -- if (e) { } elsif (e) { } else { } ** unless (e) { } elsif (e) { } else { } ! ~ \ u+ u- given (e) { when (e) {} default {} } =~ !~ * / % x NUMBERS vs STRINGS FALSE vs TRUE + - . = = undef, "", 0, "0" << >> + . anything else named uops == != eq ne < > <= >= lt gt le ge < > <= >= lt gt le ge == != <=> eq ne cmp ~~ <=> cmp & | ^ REGEX MODIFIERS REGEX METACHARS && /i case insensitive ^ string begin || // /m line based ^$ $ str end (bfr \n) .. ... /s . includes \n + one or more ?: /x /xx ign. wh.space * zero or more = += last goto /p preserve ? zero or one , => /a ASCII /aa safe {3,7} repeat in range list ops /l locale /d dual | alternation not /u Unicode [] character class and /e evaluate /ee rpts \b boundary or xor /g global \z string end /o compile pat once () capture DEBUG (?:p) no capture -MO=Deparse REGEX CHARCLASSES (?#t) comment -MO=Terse . [^\n] (?=p) ZW pos ahead -D## \s whitespace (?!p) ZW neg ahead -d:Trace \w word chars (?<=p) ZW pos behind \K \d digits (?<!p) ZW neg behind CONFIGURATION \pP named property (?>p) no backtrack perl -V:ivsize \h horiz.wh.space (?|p|p)branch reset \R linebreak (?<n>p)named capture \S \W \D \H negate \g{n} ref to named cap \K keep left part FUNCTION RETURN LISTS stat localtime caller SPECIAL VARIABLES 0 dev 0 second 0 package $_ default variable 1 ino 1 minute 1 filename $0 program name 2 mode 2 hour 2 line $/ input separator 3 nlink 3 day 3 subroutine $\ output separator 4 uid 4 month-1 4 hasargs $| autoflush 5 gid 5 year-1900 5 wantarray $! sys/libcall error 6 rdev 6 weekday 6 evaltext $@ eval error 7 size 7 yearday 7 is_require $$ process ID 8 atime 8 is_dst 8 hints $. line number 9 mtime 9 bitmask @ARGV command line args 10 ctime 10 hinthash @INC include paths 11 blksz 3..10 only @_ subroutine args 12 blcks with EXPR %ENV environment =head1 ACKNOWLEDGEMENTS The first version of this document appeared on Perl Monks, where several people had useful suggestions. Thank you, Perl Monks. A special thanks to Damian Conway, who didn't only suggest important changes, but also took the time to count the number of listed features and make a Perl 6 version to show that Perl will stay Perl. =head1 AUTHOR Juerd Waalboer <#####@juerd.nl>, with the help of many Perl Monks. =head1 SEE ALSO =over 4 =item * L<http://perlmonks.org/?node_id=216602> - the original PM post =item * L<http://perlmonks.org/?node_id=238031> - Damian Conway's Perl 6 version =item * L<http://juerd.nl/site.plp/perlcheat> - home of the Perl Cheat Sheet =back