=over

=item readpipe EXPR

=item readpipe
X<readpipe>

EXPR is executed as a system command.
The collected standard output of the command is returned.
In scalar context, it comes back as a single (potentially
multi-line) string.  In list context, returns a list of lines
(however you've defined lines with L<C<$E<sol>>|perlvar/$E<sol>> (or
C<$INPUT_RECORD_SEPARATOR> in L<English>)).
This is the internal function implementing the C<qx/EXPR/>
operator, but you can use it directly.  The C<qx/EXPR/>
operator is discussed in more detail in L<perlop/"C<qx/I<STRING>/>">.
If EXPR is omitted, uses L<C<$_>|perlvar/$_>.

=back