Does any one know how to merge multiple gdsfiles into a single gds? I'm trying to avoid installing klayout and use simpler way to do that

In open_pdks there's a script

common/create_gds_library.py

that does this. It is designed for use with open_pdks so not quite as simple as it might otherwise be (it calls magic to to the job of concatenating all the GDS files, so it has to be given the path to the startup script for magic, for example). Run the script without arguments to get usage information. There are probably simpler solutions out there. In principle all that needs to be done is to separate the core of each file from its BGNLIB and ENDLIB blocks, concatenate them all, then put the BGNLIB and ENDLIB blocks back around the concatenated data.

Thanks so much, it works easily!