The system @list form bypasses the shell, so running the process in the background is possible, but it takes a lot more code if you want to implement it yourself. Before you try to implement this yourself it's probably much easier to just use a module like IPC::Run.

system('cmd foo bar &')
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system('/bin/sh', '-c', 'cmd foo bar &')
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But you're surely asking to pass cmd, foo and bar as separate args.

We can use sh to build the command:

system('/bin/sh', '-c', '"$@" &', 'dummy', $prog, @args);
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Or we can use a Perl module to build the command:

use String::ShellQuote qw( shell_quote );

system(shell_quote($prog, @args) . ' &'));
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