Change all existing static externals in tags from operative to peg?

[Axel S]

Hello,

We have some shared libraries, and these are referenced as static 
externals in all tagged versions of our different projects.
After reorganizing the directory structure of our shared libraries, I 
see that all tagged versions now gives an error. I realised that the 
externals should have been referenced by using peg revision (@X) instead 
of operative revision (-r X).
We have hundreds of tagged versions, and inside these there are 
two-three different external references.
How can I recursively change the external definitions from operative to 
peg in my tags directories? I imagine I will need some sort of shell 
script to do the job, preferably without checking out the whole repo...
Best Regards,
Axel