How to programmatically add text to an eps file?

Question

linux

Hello.
There was a need to add certain text to an existing eps file in a certain place. The text should be in a vector, ideally - in curves (but I seem to have learned how to distill into curves through ghostscript).
Question: is there any library or ready-made console utility that can be used for these purposes? It is supposed to be used in a php application under Linux. Not php will work either.