Alan Cox (alan(a)redhat.com) said:
Fork should be pretty cheap - although that depends how much memory
is unshared
by each of the resulting tasks. A smaller cleaner shell such as rc (which was
designed for this job in plan 9) or ash might well perform better. I'm dubious
it would be a big difference but someone can bench it.
ash has been benchmarked. Required rooting out some bashisms from the scripts
(or just calling those specific scripts with bash), but in any case, it didn't
make much difference.
Bill