Actually, i do know the diff between shell and Perl, I've been programming for a few yrs now.. ;-)
From what you two are saying, it sounds like it's impossible to do what I want anyway.
I tried your use of qx, but it failed thus: 
@cmd_arr = ("someprog", "var");
$msg = qx/@cmd_arr 2>&1/;
if( $? )
{
    print "fail $?\n";
    print "$msg\n";
}

Result:
fail -1
Use of uninitialized value in concatenation (.) or string at ./err_cvt
+.pl line 17.

[download]
I read about the $? >> 8 in the Cookbook and I read the info about $! in a string context in perlvar http://perldoc.perl.org/perlvar.html#%24ERRNO, which is why I was trying to use those techniques.
I like to check rtn status' as much as possible and I've always hated the fact I can't get reliable sensible msgs from system(), so I thought I'd ask if there was a known solution.
Apparently not ... :-(

Cheers
Chris

PS any idea on Qn 3 ?

In reply to Re^2: Using system(): converting error num to human readable message by chrism01
in thread Using system(): converting error num to human readable message by chrism01

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