Cleanup .bash_profile.  Also, After trying this for a bit, I've actually found that running only history -a, without -c and -r, is better usability-wise (though it's not what the question asked). It means commands you run are available instantly in new shells even before exiting the current shell, but not in concurrently running shells. This way Arrow-Up still always selects the last-run commands of the current session, which I find much less confusing. – Jo Liss Feb 4 '12 at 15:15
http://unix.stackexchange.com/questions/1288/preserve-bash-history-in-multiple-terminal-windows#3055135