There's String::ShellQuote on CPAN.

A name that promises much more than the module actually implements. With a good amount of luck, it may work for this very specific problem ("My Perl utility generates a bash script that consists of mkdir/rsync/cp commands. This bash script is later used by users [...]"). After all, bash should be a bourne-compatible shell. But don't assume that module can do everything its name promises.

Quoting myself:

The last two times I looked at String::ShellQuote (Re^2: Passing values from Perl script to shell script in 2009 and Re^4: quoting/escaping file names in 2014), it did not look good. The last change is from 2010. So, String::ShellQuote still has the same problems as in 2009 [...]: It works just for some unnamed version of some unnamed bourne shell. The author wanted to add more shells, but he did not since 2005. The test.t look very strange, especially I don't see any reasonable test for passing arguments via a shell. So, it's old, unmaintained, not well-tested, and broken for all shells except for that unspecified bourne shell.

See also:

• Re^2: preserve quotes after $0 interpolation
• Re^3: system() call mis-directs?
• Re^4: quoting/escaping file names
• Re^2: Passing values from Perl script to shell script

Update:

I had a closer look at the source code and did some tests: Problems with String::ShellQuote

Alexander

--
Today I will gladly share my knowledge and experience, for there are no sweeter words than "I told you so". ;-)

This is more of an observation rather than answering your question but using alternative delimiters in your substitutions can make the code much easier to read. Also I find that it is easier to use the hex value for a backslash rather than the character itself, e.g. converting to Unix-style paths ...

johngg@aleatico:~$ perl -Mstrict -Mwarnings -E 'say q{};
my( $path ) = qw{ C:\Users\fred\file.txt };
say $path;
$path =~ s{\x5c}{/}g;
say $path;'

C:\Users\fred\file.txt
C:/Users/fred/file.txt
[download]

Going the other way, I would use a lookahead, the chr function and the e modifier in a substitution to do escaping.

johngg@aleatico:~$ perl -Mstrict -Mwarnings -E 'say q{};
my( $path ) = qw{ C:\Users\fred\file.txt };
say $path;
$path =~ s{(?=\x5c)}{ chr 92 }eg;
say $path;'

C:\Users\fred\file.txt
C:\\Users\\fred\\file.txt
[download]

It seems easier to my eyes. I hope this is helpful.

G'day ovedpo15,

I'd use a bracketed character class. A negated one is possibly the easiest. If you want to individually specify special characters, see "Special Characters Inside a Bracketed Character Class". Here's an example.

#!/usr/bin/env perl

use strict;
use warnings;

use Test::More;

my @tests = (
    ['a!b@c#', 'a\!b\@c\#'],
    ['{d}e(f)', '\{d\}e\(f\)'],
    [q{g"h'i}, q{g\"h\'i}],
    ['[/].\\', '\[/\].\\\\'],
);

plan tests => 0+@tests;

my $re = qr{([^0-9A-Za-z./])};

for my $test (@tests) {
    my ($got, $exp) = @$test;
    $got =~ s/$re/\Q$1/g;
    ok $got eq $exp;
}
[download]

Output:

1..4
ok 1
ok 2
ok 3
ok 4
[download]

Extend those tests with real pathnames from your application.

You may need different regexes for rsync and cp (depends on whether "except" should be "accept" or "expect" :-)

bash quoting is simple: put single quotes around the string after replacing every ' in the string with '"'"'

sub bashquote { "'" . shift =~ s/'/'"'"'/gr . "'" }
[download]

Sure, sometimes the wrapping single quotes are not needed, but if they are just around directory names and file names, they don't hurt.

Used as a base for a repair attempt for String::ShellQuote: Re: Problems with String::ShellQuote

Alexander

--
Today I will gladly share my knowledge and experience, for there are no sweeter words than "I told you so". ;-)