Like I said, backticks return a scalar, so you should run $output = `command`, though calling an input $output is a little confusing. Assuming that 'Restored successfully' is the last line and only returned on success, you could do something like:

$backup_return = `command`;
die "Backup failed: $backup_return\n" unless $backup_return=~/Restored
+ successfully/;
$other_return = `second command`;
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