How do you run an external command in perl while controlling its locale?

Question

Related to this question but more in-depth. I am running a command like the following:

foreach $dir (@dirs) {
    $cnt = `svn st $dir | wc -l`;
    if($cnt > 0){
        $content .= "$dir\n";
        $mods++;
    }
}

However the directory contains non-ASCII files and thus throws an error when the locale is incorrect or not set.

The correct way to set the locale I need in perl is

setlocale(LC_CTYPE, 'en_US.UTF-8');

However, this does not seem to be affecting the svn st command, as the locale error still occurs when the perl script is not run in a terminal with the correct locale set.

Answer 1

You need to set the environment variable for the external command:

$cnt = `LC_CTYPE=en_US.UTF-8 svn st $dir | wc -l`;

You could also change the environment of the script (%ENV), which changes the environment for any child processes:

$ENV{LC_CTYPE} = 'en_US.UTF-8';

Answer 2

Setup the environment for new processes by manipulating the %ENV hash.

$ENV{LC_CTYPE} = 'en_US.UTF-8';
$cnt = `svn ...`;