The nice way to run long-running batch files
such as batch.g, which computes the cohomology
groups for all groups of size 16, is on someone
else's machine. Your department probably has
a machine set up just for this purpose. Log on to
this machine and invoke the script as follows.

nice nohup gap -o 1000M batch.g &

and then log out of the machine while the 
program runs. Come back later for the results
and kill the GAP process.
Do this on Saturday or at night if possible.
