perlcheat

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 pro-
       grammers. Not everything is mentioned, but 194 features may already be
       overwhelming.

       The sheet

	 CONTEXTS  SIGILS	      ARRAYS	    HASHES
	 void	   $scalar   whole:   @array	    %hash
	 scalar	   @array    slice:   @array[0, 2]  @hash{’a’, ’b’}
	 list	   %hash     element: $array[0]	    $hash{’a’}
		   &sub
		   *glob    SCALAR VALUES
			    number, string, reference, glob, undef
	 REFERENCES
	 \     references      $$foo[1]	      aka $foo->[1]
	 $@%&* dereference     $$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	 =	    =	     perl.plover.com
	 ->			 +	    .	     search.cpan.org
	 ++ --			 == !=	    eq ne	  cpan.org
	 **			 < > <= >=  lt gt le ge	  pm.org
	 ! ~ \ u+ u-		 <=>	    cmp		  tpj.com
	 =~ !~						  perldoc.com
	 * / % x		 SYNTAX
	 + - .			 for	(LIST) { }, for (a;b;c) { }
	 << >>			 while	( ) { }, until ( ) { }
	 named uops		 if	( ) { } elsif ( ) { } else { }
	 < > <= >= lt gt le ge	 unless ( ) { } elsif ( ) { } else { }
	 == != <=> eq ne cmp	 for equals foreach (ALWAYS)
	 &
	 │ ^		  REGEX METACHARS	     REGEX MODIFIERS
	 &&		  ^	string begin	     /i case insens.
	 ││		  $	str. end (before \n) /m line based ^$
	 .. ...		  +	one or more	     /s . includes \n
	 ?:		  *	zero or more	     /x ign. wh.space
	 = += -= *= etc.  ?	zero or one	     /g global
	 , =>		  {3,7} repeat in range
	 list ops	  ()	capture		 REGEX CHARCLASSES
	 not		  (?:)	no capture	 .  == [^\n]
	 and		  []	character class	 \s == [\x20\f\t\r\n]
	 or xor		  │	alternation	 \w == [A-Za-z0-9_]
			  \b	word boundary	 \d == [0-9]
			  \z	string end	 \S, \W and \D negate
	 DO
	 use strict;	    DON’T	     LINKS
	 use warnings;	    "$foo"	     perl.com
	 my $var;	    $$variable_name  perlmonks.org
	 open() or die $!;  ‘$userinput‘     use.perl.org
	 use Modules;	    /$userinput/     perl.apache.org
					     parrotcode.org
	 FUNCTION RETURN LISTS
	 stat	   localtime	caller	       SPECIAL VARIABLES
	  0 dev	   0 second	0 package      $_    default variable
	  1 ino	   1 minute	1 filename     $0    program name
	  2 mode   2 hour	2 line	       $/    input separator
	  3 nlink  3 day	3 subroutine   $\    output separator
	  4 uid	   4 month-1	4 hasargs      $│    autoflush
	  5 gid	   5 year-1900	5 wantarray    $!    sys/libcall error
	  6 rdev   6 weekday	6 evaltext     $@    eval error
	  7 size   7 yearday	7 is_require   $$    process ID
	  8 atime  8 is_dst	8 hints	       $.    line number
	  9 mtime		9 bitmask      @ARGV command line args
	 10 ctime  just use		       @INC  include paths
	 11 blksz  POSIX::	3..9 only      @_    subroutine args
	 12 blcks  strftime!	with EXPR      %ENV  environment

ACKNOWLEDGEMENTS
       The first version of this document appeared on Perl Monks, where sev-
       eral 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@cpan.org>, 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 v5.8.8			  2006-01-07			 PERLCHEAT(1)