Making a system call that returns the stdout output as a string

Question

Perl and PHP do this with backticks. For example,

$output = `ls`;

Returns a directory listing. A similar function, system(\"foo\")

Answer 1

Yet another way to do it in Perl (TIMTOWTDI)

$output = <<`END`;
ls
END

This is specially useful when embedding a relatively large shell script in a Perl program

Answer 2

Python:

import os
output = os.popen("foo").read()

Answer 3

In shell

OUTPUT=`ls`

or alternatively

OUTPUT=$(ls)

This second method is better because it allows nesting, but isn't supported by all shells, unlike the first method.

Answer 4

Yet another way (or 2!) in Perl....

open my $pipe, 'ps |';
my @output = < $pipe >;
say @output;

open can also be written like so...

open my $pipe, '-|', 'ps'

Answer 5

Clozure Common Lisp:

(with-output-to-string (stream)
   (run-program "ls" '("-l") :output stream))

LispWorks

(with-output-to-string (*standard-output*)
  (sys:call-system-showing-output "ls -l" :prefix "" :show-cmd nil))

Answer 6

Mathematica:

output = Import["!foo", "Text"];