# step1.pl
print "This is step1.\n";
exit 0;

# step2.pl
print "This is step2.\n";
exit 0;

# step3.pl
print "This is step3.\n";
exit 42;

# step4.pl
print "This is step4.\n";
exit 0;

##</code><code>##

# runner.pl
use strict;
use warnings;
$| = 1;
my @scripts = ('step1.pl', 'step2.pl', 'step3.pl', 'step4.pl');
for my $scr (@scripts) {
    my $cmd = "$^X $scr";
    print "Run '$cmd'...";
    my $out = qx{$cmd};
    my $rc = $? >> 8;
    print "rc=$rc\n";
    print "Output:$out\n";
    if ($rc != 0) {
        print "Main script $0 exit $rc\n";
        exit $rc;
    }
}
print "All commands finished successfully.\n";