Knowing what sort of data and from what format would be helpful. XML documents are just text documents though, so you can go from very simple bash scripts, m4 t

Knowing what sort of data and from what format would be helpful. XML documents are just text documents though, so you can go from very simple bash scripts, m4 templates, moustache templates, and many others. Personally I go for shell scripts (and heredocs) for simple things and awk + m4 for more complex data driven things. Anything more complicated than that and fprintf from a real language is better, although less ergonomic.