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PERLCHEAT(1)                          Perl Programmers Reference Guide                          PERLCHEAT(1)



NAME
       perlcheat - Perl 5 Cheat Sheet

DESCRIPTION
       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
         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
                                NUMBERS vs STRINGS    LINKS
         OPERATOR PRECEDENCE    =          =          perldoc.perl.org
         ->                     +          .           search.cpan.org
         ++ --                  == !=      eq ne              cpan.org
         **                     < > <= >=  lt gt le ge          pm.org
         ! ~ \ u+ u-            <=>        cmp                p3rl.org
         =~ !~                                           perlmonks.org
         * / % x                SYNTAX
         + - .                  foreach (LIST) { }     for (a;b;c) { }
         << >>                  while   (e) { }        until (e)   { }
         named uops             if      (e) { } elsif (e) { } else { }
         < > <= >= lt gt le ge  unless  (e) { } elsif (e) { } else { }
         == != <=> eq ne cmp ~~ given   (e) { when (e) {} default {} }
         &
         | ^             REGEX METACHARS          REGEX MODIFIERS
         &&              ^      string begin      /i case insensitive
         || //           $      str end (bfr \n)  /m line based ^$
         .. ...          +      one or more       /s . includes \n
         ?:              *      zero or more      /x ignore wh.space
         = += -= *= etc  ?      zero or one       /p preserve
         , =>            {3,7}  repeat in range   /a ASCII    /aa safe
         list ops        |      alternation       /l locale   /d  dual
         not             []     character class   /u Unicode
         and             \b     word boundary     /e evaluate /ee rpts
         or xor          \z     string end        /g global
                         ()     capture           /o compile pat once
         DEBUG           (?:p)  no capture
          -MO=Deparse    (?#t)  comment           REGEX CHARCLASSES
          -MO=Terse      (?=p)  ZW pos ahead      .   [^\n]
          -D##           (?!p)  ZW neg ahead      \s  whitespace
          -d:Trace       (?<=p) ZW pos behind \K  \w  word chars
                         (?<!p) ZW neg behind     \d  digits
         CONFIGURATION   (?>p)  no backtrack      \pP named property
         perl -V:ivsize  (?|p|p)branch reset      \h  horiz.wh.space
                         (?&NM) cap to name       \R  linebreak
                                                  \S \W \D \H negate
         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

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



perl v5.16.2                                     2012-10-25                                     PERLCHEAT(1)