What is the longest time until you're out of patience? I once migrated many xls files (around 2-3 MG each) into mysql. Each file took like forever but the process eventually ended successfully. Once or twice, I did open a file manually only to save (as) it again under the same name. This made the file size smaller dan the process went faster. But doing this for 30-40 files wasn't an option at all, and I couldn't find any way to automate this on Linux. So I just enjoyed my time doing something else while waiting the migration process to do its job, especially after I did prog.pl /path/to/dir/*.xls.