perlcheat (1) Linux Manual Page

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 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

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

Index