perlcheat(1)

1PERLCHEAT(1)           Perl Programmers Reference Guide           PERLCHEAT(1)
2
3
4

NAME

6       perlcheat - Perl 5 Cheat Sheet
7

DESCRIPTION

9       This 'cheat sheet' is a handy reference, meant for beginning Perl pro‐
10       grammers. Not everything is mentioned, but 194 features may already be
11       overwhelming.
12
13       The sheet
14
15         CONTEXTS  SIGILS             ARRAYS        HASHES
16         void      $scalar   whole:   @array        %hash
17         scalar    @array    slice:   @array[0, 2]  @hash{'a', 'b'}
18         list      %hash     element: $array[0]     $hash{'a'}
19                   &sub
20                   *glob    SCALAR VALUES
21                            number, string, reference, glob, undef
22         REFERENCES
23         \     references      $$foo[1]       aka $foo->[1]
24         $@%&* dereference     $$foo{bar}     aka $foo->{bar}
25         []    anon. arrayref  ${$$foo[1]}[2] aka $foo->[1]->[2]
26         {}    anon. hashref   ${$$foo[1]}[2] aka $foo->[1][2]
27         \()   list of refs
28                                 NUMBERS vs STRINGS  LINKS
29         OPERATOR PRECEDENCE     =          =        perl.plover.com
30         ->                      +          .        search.cpan.org
31         ++ --                   == !=      eq ne         cpan.org
32         **                      < > <= >=  lt gt le ge   pm.org
33         ! ~ \ u+ u-             <=>        cmp           tpj.com
34         =~ !~                                            perldoc.com
35         * / % x                 SYNTAX
36         + - .                   for    (LIST) { }, for (a;b;c) { }
37         << >>                   while  ( ) { }, until ( ) { }
38         named uops              if     ( ) { } elsif ( ) { } else { }
39         < > <= >= lt gt le ge   unless ( ) { } elsif ( ) { } else { }
40         == != <=> eq ne cmp     for equals foreach (ALWAYS)
41         &
42         ⎪ ^              REGEX METACHARS            REGEX MODIFIERS
43         &&               ^     string begin         /i case insens.
44         ⎪⎪               $     str. end (before \n) /m line based ^$
45         .. ...           +     one or more          /s . includes \n
46         ?:               *     zero or more         /x ign. wh.space
47         = += -= *= etc.  ?     zero or one          /g global
48         , =>             {3,7} repeat in range
49         list ops         ()    capture          REGEX CHARCLASSES
50         not              (?:)  no capture       .  == [^\n]
51         and              []    character class  \s == [\x20\f\t\r\n]
52         or xor           ⎪     alternation      \w == [A-Za-z0-9_]
53                          \b    word boundary    \d == [0-9]
54                          \z    string end       \S, \W and \D negate
55         DO
56         use strict;        DON'T            LINKS
57         use warnings;      "$foo"           perl.com
58         my $var;           $$variable_name  perlmonks.org
59         open() or die $!;  `$userinput`     use.perl.org
60         use Modules;       /$userinput/     perl.apache.org
61                                             parrotcode.org
62         FUNCTION RETURN LISTS
63         stat      localtime    caller         SPECIAL VARIABLES
64          0 dev    0 second     0 package      $_    default variable
65          1 ino    1 minute     1 filename     $0    program name
66          2 mode   2 hour       2 line         $/    input separator
67          3 nlink  3 day        3 subroutine   $\    output separator
68          4 uid    4 month-1    4 hasargs      $⎪    autoflush
69          5 gid    5 year-1900  5 wantarray    $!    sys/libcall error
70          6 rdev   6 weekday    6 evaltext     $@    eval error
71          7 size   7 yearday    7 is_require   $$    process ID
72          8 atime  8 is_dst     8 hints        $.    line number
73          9 mtime               9 bitmask      @ARGV command line args
74         10 ctime  just use                    @INC  include paths
75         11 blksz  POSIX::      3..9 only      @_    subroutine args
76         12 blcks  strftime!    with EXPR      %ENV  environment
77

ACKNOWLEDGEMENTS

79       The first version of this document appeared on Perl Monks, where sev‐
80       eral people had useful suggestions. Thank you, Perl Monks.
81
82       A special thanks to Damian Conway, who didn't only suggest important
83       changes, but also took the time to count the number of listed features
84       and make a Perl 6 version to show that Perl will stay Perl.
85

AUTHOR

87       Juerd Waalboer <juerd@cpan.org>, with the help of many Perl Monks.
88

NAME

DESCRIPTION

ACKNOWLEDGEMENTS

AUTHOR

SEE ALSO