First of all, what does "last part" mean ? It means "all characters after some special character". For example, if that character is "-", then the "last part" of "1574-114687-415" is "415" and the "last part" of "jg7e;f,k-e" is "e".

So, yeah, how do I extract the "last part" of a string (you can provide examples with the "-") ?

edit that's surely not informative, but I am using Ubuntu 13.04

I did this using sed, a stream editor. echo  "1574-114687-415" | sed s/.*-// will replace everything at the beginning of a string that has a - at the end with nothing, and continue on in this way. It returns everything which doesn't have a - after it.