perlcheat - Perl 5 Cheat Sheet
This 'cheat sheet' is a handy reference, meant for beginning Perl programmers. Not everything is mentioned, but 195 features may already be overwhelming.
The sheet
1. CONTEXTS SIGILS ref ARRAYS HASHES 2. void $scalar SCALAR @array %hash 3. scalar @array ARRAY @array[0, 2] @hash{'a', 'b'} 4. list %hash HASH $array[0] $hash{'a'} 5. &sub CODE 6. *glob GLOB SCALAR VALUES 7. FORMAT number, string, ref, glob, undef 8. REFERENCES 9. \ reference $$foo[1] aka $foo->[1] 10. $@%&* dereference $$foo{bar} aka $foo->{bar} 11. [] anon. arrayref ${$$foo[1]}[2] aka $foo->[1]->[2] 12. {} anon. hashref ${$$foo[1]}[2] aka $foo->[1][2] 13. \() list of refs 14. NUMBERS vs STRINGS LINKS 15. OPERATOR PRECEDENCE = = perldoc.perl.org 16. -> + . search.cpan.org 17. ++ -- == != eq ne cpan.org 18. ** < > <= >= lt gt le ge pm.org 19. ! ~ \ u+ u- <=> cmp p3rl.org 20. =~ !~ perlmonks.org 21. * / % x SYNTAX 22. + - . foreach (LIST) { } for (a;b;c) { } 23. << >> while (e) { } until (e) { } 24. named uops if (e) { } elsif (e) { } else { } 25. < > <= >= lt gt le ge unless (e) { } elsif (e) { } else { } 26. == != <=> eq ne cmp ~~ given (e) { when (e) {} default {} } 27. & 28. | ^ REGEX METACHARS REGEX MODIFIERS 29. && ^ string begin /i case insensitive 30. || // $ str end (bfr \n) /m line based ^$ 31. .. ... + one or more /s . includes \n 32. ?: * zero or more /x ignore wh.space 33. = += -= *= etc ? zero or one /p preserve 34. , => {3,7} repeat in range /a ASCII /aa safe 35. list ops | alternation /l locale /d dual 36. not [] character class /u Unicode 37. and \b word boundary /e evaluate /ee rpts 38. or xor \z string end /g global 39. () capture /o compile pat once 40. DEBUG (?:p) no capture 41. -MO=Deparse (?#t) comment REGEX CHARCLASSES 42. -MO=Terse (?=p) ZW pos ahead . [^\n] 43. -D## (?!p) ZW neg ahead \s whitespace 44. -d:Trace (?<=p) ZW pos behind \K \w word chars 45. (?<!p) ZW neg behind \d digits 46. CONFIGURATION (?>p) no backtrack \pP named property 47. perl -V:ivsize (?|p|p)branch reset \h horiz.wh.space 48. (?&NM) cap to name \R linebreak 49. \S \W \D \H negate 50. FUNCTION RETURN LISTS 51. stat localtime caller SPECIAL VARIABLES 52. 0 dev 0 second 0 package $_ default variable 53. 1 ino 1 minute 1 filename $0 program name 54. 2 mode 2 hour 2 line $/ input separator 55. 3 nlink 3 day 3 subroutine $\ output separator 56. 4 uid 4 month-1 4 hasargs $| autoflush 57. 5 gid 5 year-1900 5 wantarray $! sys/libcall error 58. 6 rdev 6 weekday 6 evaltext $@ eval error 59. 7 size 7 yearday 7 is_require $$ process ID 60. 8 atime 8 is_dst 8 hints $. line number 61. 9 mtime 9 bitmask @ARGV command line args 62. 10 ctime 10 hinthash @INC include paths 63. 11 blksz 3..10 only @_ subroutine args 64. 12 blcks with EXPR %ENV environment |
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.
AUTHOR
Juerd Waalboer <#####@juerd.nl>, with the help of many Perl Monks.
SEE ALSO • http://perlmonks.org/?node_id=216602 - the original PM post
• http://perlmonks.org/?node_id=238031 - Damian Conway's Perl 6 version
• http://juerd.nl/site.plp/perlcheat - home of the Perl Cheat Sheet