Perl release summary
The most significant features introduced for recent versions of the Perl
scripting language.
Core security support is provided for 3 years, so typical users should run at least 5.36.
Stable distributions such as Debian 11 maintain 5.32+.
Enterprise platforms retain versions up to 5.14.
5.40 2024-06-09: latest stable release
use v5.40- import builtin functions and enable the try feature
__CLASS__- keyword to reference to the current class name, similar to
__PACKAGE__ (feature)
:reader- attribute for field variables to create corresponding accessor methods (feature)
^^- higher precedence logical
xor operator, as || is to or
builtin::inf, builtin::nan- constants equivalent to special floating point values infinity and Not a Number
use Test2::Suite- comprehensive set of test tools for writing unit tests, providing a drop in replacement to
Test::More
5.38 2023-07-02: active core support
use feature "module_true"- packages implicitly return true, enabled along with
no feature "bareword_filehandles" (bundled)
sub ($var ||= default)- assign values when false (or undefined on
//=) instead of omitted
/(*{ … })/- optimistic eval:
(?{ … }) with regex optimisations enabled
class- define object classes: packages with
field variables and method subroutines (feature, experimental)
${^LAST_SUCCESSFUL_PATTERN}- explicit variable to access the previous match as in
s//…/
%{^HOOK}- perform tasks
require__before and require__after when calling require
- Unicode
- v15.0
5.36 2022-05-28: official security patches
use v5.36- use
warnings; use feature qw'signatures isa'; no feature qw'indirect multidimensional switch'
use builtin- namespace for interpreter functions, such as
weaken and blessed from Scalar::Util, ceil/floor from POSIX, and trim like String::Util (experimental until 5.40 then bundled)
is_bool(!0)- distinguish scalar variable types (by
builtin functions) for data interoperability
for my ($k, $v) (%hash)- iterate over multiple values at a time (including
builtin::indexed for arrays) (feature, experimental until 5.40)
defer {}- queue code to be executed when going out of scope (feature, experimental)
try {} finally {}- run code at the end of a
try construct regardless of failure (feature, experimental)
- unicode delimiters for quoting operators (experimental)
sub ($var) {!pop}- signatured subs are stable, but mixing with the arguments array
@_ remains experimental (feature, experimental)
$SIG{FPE}- floating-point exceptions no longer deferred but delivered immediately like other signals
- perl
-g - disable input record separator (slurp mode), alias for
-0777
- Unicode
- v14.0
5.34 2021-05-20
try {} catch- exception handling similar to eval blocks (feature, experimental until 5.40 then bundled)
/{,n}/- empty lower bound quantifier is accepted as shorthand for 0
\x{ … }- insignificant space within curly braces, also for
\b{}, \g{}, \k{}, \N{}, \o{} as well as /{m,n}/ quantifiers
0o0- octal prefix
0o alternative to 0… and oct
re::optimization(qr//)- debug regular expression optimization information discovered at compile time
no feature …- disable discouraged practices of
multidimensional and bareword_filehandles array emulation (bundled in 5.36 and 5.38)
5.32 2020-06-20: still maintained by common vendors
isa- infix operator to check class instance (feature, experimental until 5.36 then bundled)
$min < $_ <= $max- chained comparison repeats inner part as
$min < $_ and $_ <= $max
/\p{Name=$var}/- match Unicode Name property like
\N{} but with interpolation and subpatterns
open F, '+>>', undef- respect append mode on temporary files with mixed access
no feature 'indirect'- disable indirect object notation such as
new Class instead of Class->new (bundled in 5.36)
- streamzip
- program distributed with core IO::Compress::Base to compress stdin into a zip container
- Unicode
- v13.0
5.30 2019-05-22
/(?<=var+)- variable length lookbehind assertions (experimental until 5.36)
m(\p{nv=/.*/})- match unicode properties by regular expressions (experimental)
my $state if 0- workaround for
state (deprecated since v5.10!) is now prohibited
qr'\N'- Delimiters must be graphemes; unescaped
{ illegal; \N in single quotes
- Unicode
- v12.1
5.28 2018-06-22
delete %hash{…}- hash slices can be deleted with key+value pairs
/(*…)/- alphabetic synonyms for assertions, e.g.
(*atomic:…) for (?>…) and (*nlb:…) for (?<!…) (experimental until 5.31.6)
/(*script_run:)/- enforces all characters to be from the same script (experimental until 5.31.6)
state @a- persistent lexical array or hash variables (in addition to scalars)
- perl
-i -pe die - safe in-place editing: files are replaced only after successful completion
${^SAFE_LOCALES}- locales are thread-safe on supported systems, indicated by this variable
- Unicode
- v10.0
5.26 2017-05-30
use lib '.'- current directory no longer included in default module search path
@INC
<<~EOT- indented here-docs, strips same whitespace before delimiter in each line
@{^CAPTURE}- array of last match's captures, so
${^CAPTURE}[0] is $1
//xx- extended modifier to also ignore whitespace in bracketed character classes
use Test2::V0- generic testing framework to replace
Test::* and TAP::*
- Unicode
- v9.0
5.24 2016-05-09
printf '%.*2$x'- reordered precision arguments
/\b{lb}/- line break boundary type (position suitable for hyphenation)
/faster/- various significant speedups, notably matching fixed substrings,
/i on caseless languages, 64-bit arithmetic, scope overhead
- Unicode
- v8.0
5.22 2015-06-01
\$alias =- aliasing via reference (scoped as of v5.25.3) (experimental)
<<…>>- safe
readline ignoring open flags in arguments
/()/n- flag to disable numbered capturing, turning
() into (?:)
/\b{}/- boundary types: gcb (grapheme cluster), sb (sentence), wb (word)
&.& | ^ ~ consistently numeric, dotted operators for strings (feature, experimental until 5.28 then bundled)
use re 'strict'- apply stricter syntax rules to regular expression patterns (experimental)
0x.beep+0- hexadecimal floating point notation with binary power;
printf '%a' to display
??- single match shorthand (deprecated since v5.14) requires the operator
m?PATTERN?
use CGI- deprecated interface for serving http requests removed from core, see CGI::Alternatives
- Unicode
- v7.0
5.20 2014-05-27: extended vendor support 202X
sub ($var)- subroutine signatures (feature, experimental until 5.36 then bundled)
%hash{…}- hash slices return key+value pairs
[]->@*- postfix dereferencing (also e.g.
$scalar->$* for $$scalar) (feature, experimental until 5.24 then bundled)
use warnings 'once'; $a- variables $a and $b are exempt from used once warnings
- Unicode
- v6.3
5.18 2013-05-18
- PERL_PERTURB_KEYS=1
- hash overhaul; order is randomised instead of being semi-repeatable {
each %{{%hash}} ne each %{{%hash}}}
${^LAST_FH}- last read filehandle (used by
$.)
/(?[ a + b ])/- regex set operations (character subtraction
-, union +, intersection &, xor ^) (experimental until 5.36)
my sub- lexical subroutines (also
state, our); buggy before v5.22 (experimental until 5.26)
next $expression- loop controls allow runtime expressions
no warnings 'experimental::…'- mechanism for experimental features, as of now required for smartmatch
- Unicode
- v6.2
5.16 2012-05-20
__SUB__- current subroutine reference (feature, bundled)
fc, "\F"- unicode foldcase to compare case-insensitively (feature, bundled)
"\N{}"- automatic
use charnames qw( :full :short )
- Unicode
- v6.1
5.14 2011-05-14
s///r- non-destructive substitution
/(?{ m() })/- regular expressions can be nested in
/(?{})/ and /(??{})/ (experimental until 5.20)
/dalu- regexp modifiers to restrict character classes: either default, ascii, locale, or unicode semantics.
use re '/flags'- customise default modifiers
/(?^)/- construct to reset to default modifiers
FH->method- filehandle method calls load IO::File on demand (eg.
STDOUT->flush)
\o{}- escape sequence for octal values beyond 0777
package {}- package declaration in scope of code block only
multiple: labels:- statement labels allowed in all places, even before other labels
use JSON- interface with data in JavaScript Object Notation {
decode_json <>}
- Unicode
- v6.0+#8
5.12 2010-04-12
package versionpackage NAME VERSION shorthand for our $VERSION
...- yada-yada operator: code placeholder
use 5.012- implicit
strict if use VERSION >= v5.12
… whenwhen is now allowed to be used as a statement modifier
use overload 'qr'- customisable conversion to regular expressions
/\N/- inverse \n to match any character except newline regardless of
/s (experimental until 5.18)
- Unicode
- v5.2
5.10 2007-12-18: supported commercially until 2024
use v5.10- minimal perl version with bundled features (pragma to lexically enable backwards-incompatible syntax)
//- defined-or operator
~~- smart-match operator to compare different data types (updated in v5.10.1) (experimental)
say- print with newline, equivalent to
print @_, "\n" (feature, bundled)
given- switch statement to smart-match with
when/default (feature, experimental, bundled)
/(?<name>)/- named capture buffers into
%+
/(?1)/- recursive regular expression patterns
/(?|)/- resets capture numbering for each contained branch
/.++/- possessive quantifiers
?+, *+, ++ to match greedily
s/keep\K//- floating positive lookbehind, efficient alternative for
s/(keep)/$1/
/p- optionally preserve
${^MATCH} variables (avoiding $& penalty until COW in v5.20)
/\v/, /\h/- vertical and horizontal whitespace escapes (
\V \H to invert); also /\R/ for newlines
state- persistent
my variables (scalars only until 5.28) (feature, bundled)
use autodie- replace builtin functions to throw exceptions instead of returning failure {
eval {open ...} or $@->matches("open") || die}
use IO::Compress::Zip- various file compression standards {
zip IO::Uncompress::Gunzip->new("test.gz") => "recompressed.zip"}
use Time::Piece- timestamps as objects {
localtime->year > 1900}
use File::Fetch- generic data retrieval/download {
File::Fetch->new(uri => "http://localhost/")->fetch(to => \$slurp)}
- Unicode
- v5.0.0
5.8 2002-07-18: stable minimum upto 2021
no utf8- full unicode support,
utf8 pragma only for script encoding
use open- file handle behaviour altered by PerlIO layers {
binmode $fh, ":bytes"}
open $fh, '-|', @cmd- open list to fork a command without spawning a shell
open $fh, '>', \$var- perl scalars as virtual files
printf '%1$s', @args- syntax to use parameters out of order
1_2_3 == 123- underscores between digits allowed in numeric constants
use bignum- transparent big number support {
length 1e100 == 101}
use if- conditional module inclusion {
no if $] >= 5.022, "warnings", "redundant"}
use Digest- calculate various message digests (data hashes) {
$hash = sha256_hex($data)}
use Encode- character set conversion {
encode("utf8", decode("iso-8859-1", $octets))}
use File::Temp- create a temporary file or directory safely {
$fh = tempfile();}
use List::Util- general-utility list subroutines {
@cards = shuffle 0..51}
use Locale::Maketext- various localization and internationalization in
Locale::* and L18N::*
use Memoize- remember function results, trading space for time {
memoize "stat"}
use MIME::Base64- base64 encoded strings as in email attachments
use Test::More- modern framework for unit testing {
is $got, $expected}
use Time::HiRes- high resolution timers {
$μs = [gettimeofday]; sleep .1; $elapsed = tv_interval $μs}
- Unicode
- v3.2.0
5.6 2000-03-23: start of modern compatibility
use warnings- pragma to enable warnings in lexical scope
use utf8- experimental unicode semantics (completed in v5.8) (experimental until 5.8)
use charnames- string escape
\N{} to insert named character
our- declare global variables
v1.2.3- represent strings as vector of ordinals, useful in version numbers (
printf '%vd' to display)
0b0- binary numbers in literals,
printf '%b', and oct
sub :lvalue- subroutine attribute to return a modifiable value (experimental until 5.20)
open my $fh, $mode, $expr- file handles in scoped scalars, third argument for unambiguous file name
pack 'q'- 64-bit integer support (also large files >2GiB) (experimental until 5.8.1)
sort $coderef ()- comparison function can be a subroutine reference; prototype
($$) to pass elements as normal @_
CHECK {}- special block called at end of compilation
/[[:…:]]/- POSIX character class syntax such as
/[[:alpha:]]/
- Unicode
- v3.0.1