IPC::Open3 works like IPC::Open2.
The following differences apply:use IPC::Open3; $pid = open3($wtr, $rdr, $err, $cmd_with_args); $pid = open3($wtr, $rdr, $err, $cmd, "arg1", "arg2", ...);
The first two arguments ($wtr and $rdr) are passed in
the opposite order.
A third filehandle can be passed, for standard error. If this argument is
given as "", then STDERR and STDOUT for $cmd
are on the same filehandle.
If $wtr begins with
<, then the leading < is
stripped from the name and the remainder is assumed to be a regular filehandle
for an open file, rather than a reference to a typeglob.
open3 opens this file as STDIN for
$cmd and closes it in the parent. Likewise, if
$rdr or $err begins with >, then $cmd directs
STDOUT or STDERR directly to that file rather than to the parent.