This entry was originally submitted to Debian Package of the day, but rejected because make is well known. Figure 1:The file In is used to produce InterM that is itself used to produce Out. Therefore Out depends directly on InterM and indirectly on In. I agree that most programmers and administrators know GNU make. Sadly, it is ignored by most others. GNU make solves a very common problem that everyone faces when processing more than one file with more than one programm. It keeps track which file has been changed and which files have to be regenerated.