Currently ~/.parallel/ is used for locks, control paths for -M, and temporary files for loadavg and swap_activity. This is chosen because if you run on multiple servers ~/ is likely to be shared amongst them, where as /tmp is likely to be local to the machine. And you want a shared lock so that if you run 'sem --id foo' then only one process is being run no matter how many machines it is being run on.
Apparently some users do not have write access to their home dir(!), so I am considering having a variable so you can point ~/.parallel to another place. $PARALLELDIR or $PARALLEL_DIR seem like reasonable choices for me. They will of course default to ~/.parallel. Do you have a better idea for solving the issue or for the variable name? /Ole
