How can I run external programs using Perl 6? (e.g. like “system” in Perl 5)

Question

I can use system in Perl 5 to run external programs. I like to think of system like a miniature "Linux command line" inside Perl. However, I cannot find documentation for system in Perl 6. What is the equivalent?

Answer 1

In addition to using shell or run, which replace system from Perl 5, you can also use NativeCall to invoke the libc system function.

On my Windows box, it looks like this:

use NativeCall;
sub system(Str --> int32) is native("msvcr110.dll") { * };
system("echo 42");

Answer 2

Perl6 actually has two commands that replace system from Perl 5.

In Perl6, shell passes its argument to the shell, similar to Perl 5's system when it has one argument that contains metacharacters.

In Perl6, run tries to avoid using the shell. It takes its first argument as a command and the remaining arguments as arguments to that command, similar to Perl 5's system when it has multiple arguments.

For example:

shell('ls > file.log.txt');   # Capture output from ls (shell does all the parsing, etc)

run('ls','-l','-r','-t');     # Run ls with -l, -r, and -t flags
run('ls','-lrt');             # Ditto

See also this 2014 Perl 6 Advent post on "running external programs".