Perl: where is the command in system("command -v wget") documented?

[Regid Ichira <regid23@nt1.in>]

  I am a perl beginner.  I stambled upon a perl line

    if (system("command -v wget >/dev/null 2>&1") == 0)

I was able to find perl's documentation for system.  But where is
the documentation for command?
  Am I right that that line tests whether wget is installed in the
system?  How does it do that?