---
name: "String::Glob::Permute"
section: "3pm"
platform: "linux"
package: "libstring-glob-permute-perl"
version: "0.01-4"
release: "Debian 13 (Trixie)"
platforms: ["linux"]
url: "https://new.carta.tech/String::Glob::Permute"
---

# String::Glob::Permute(3pm)

Expand {foo,bar,baz}\[2-4\] style string globs

## NAME

String::Glob::Permute - Expand {foo,bar,baz}\[2-4\] style string globs

## SYNOPSIS

```
    use String::Glob::Permute qw( string_glob_permute );
    my $pattern = "host{foo,bar,baz}[2-4]";
    for my $host (string_glob_permute( $pattern )) {
        print "$host\n";
    }
      # hostfoo2
      # hostbar2
      # hostbaz2
      # hostfoo3
      # hostbar3
      # hostbaz3
      # hostfoo4
      # hostbar4
      # hostbaz4
```

## DESCRIPTION

The `"string_glob_permute()"` function provided by this module expands  glob-like notations in text strings and returns all possible permutations.

For example, to run a script on hosts host1, host2, and host3, you might write

```
    @hosts = string_glob_permute( "host[1-3]" );
```

and get a list of hosts back: ("host1", "host2", "host3").

Ranges with gaps are also supported, just separate the blocks by commas:

```
    @hosts = string_glob_permute( "host[1-3,5,9]" );
```

will return ("host1", "host2", "host3", "host5", "host9").

And, finally, using curly brackets and comma-separated lists of strings, as in

```
    @hosts = string_glob_permute( "host{dev,stag,prod}" );
```

you'll get permutations with each of the alternatives back: ("hostdev", "hoststag", "hostprod") back.

All of the above can be combined, so

```
    my @hosts = string_glob_permute( "host{dev,stag}[3-4]" );
```

will result in the permutation ("hostdev3", "hoststag3", "hostdev4", "hoststag4").

The patterns allow numerical ranges only \[1-3\], no string ranges like  \[a-z\]. Pattern must not contain blanks.

The function returns a list of string permutations on success and `"undef"` in case of an error. A warning is also issued if the pattern cannot be recognized.

### Zero padding

An expression like

```
    @hosts = string_glob_permute( "host[8-9,10]" );
      # ("host8", "host9", "host10")
```

will expand to ("host8", "host9", "host10"), featuring no zero-padding to create equal-length entries. If you want ("host08", "host09", "host10"), instead, pad all integers in the range expression accordingly:

```
    @hosts = string_glob_permute( "host[08-09,10]" );
      # ("host08", "host09", "host10")
```

### Note on Perl's internal Glob Permutations

Note that there's a little-known feature within Perl itself that does  something similar, for example

```
    print "$_\n" for < foo{bar,baz} >;
```

will print

```
    foobar
    foobaz
```

if there is no file in the current directory that matches that pattern. String::Glob::Permute, on the other hand, expands irrespective of matching files, by simply always returning all possible permutations. It's also worth noting that Perl's internal Glob Permutation does not support String::Glob::Permute's \[m,n\] or \[m-n\] syntax.

## COPYRIGHT & LICENSE

Copyright (c) 2008 Yahoo! Inc. All rights reserved. The copyrights to the contents of this file are licensed under the Perl Artistic License (ver. 15 Aug 1997).

## AUTHOR

Algorithm, Code: Rick Reed, Ryan Hamilton, Greg Olszewski.  Module: 2008, Mike Schilli \<cpan@perlmeister.com\>