this is not a command:
Code:
-L/usr/lib/gcc/x86_64-linux-gnu/3.4.6/ -lgcc_s
but part of the previous one. Probably that was split into two [or more] lines, but you need to execute it in one.
So try this:
Code:
g77 -o reac reac.o poten.o ffopt.o shanno.o version.o vibra.o blas.o -L/usr/lib/gcc/x86_64-linux-gnu/3.4.6/ -lgcc_s
If this does not help please give us more details about what's going on. Dropping in an error message is usually not enough to diagnose.