Something has been gnawing at me for a while now and I can't seem to find a relevant answer either in man pages or using your 'Don't be evil' search engine.

My .bashrc has the following:

shopt -s histappend
HISTSIZE=100
HISTFILESIZE=0   # 200 previous value

Putting HISTFILESIZE to 0 allows me to start with a clean history slate with each new term window.

I find it practical in conjunction with using a prompt that contains \#, because when visualizing a previous command before recalling it with !n or !-p, one can just do:

$ history | more 

to see its relevant "n" value

In my case, usually the result of:

$ \history | tail -1 | awk '{print $1}'   # (I know this is an overkill, don't flame me)

equals the expanded value of # in PS1 minus 1, which is how I like it to be at all times. But then, sometimes not. At times the expanded value of # sort of "runs away". It's incremented in such a a manner that it becomes > than

$(( $(\history | tail -1 | awk '{print $1}')+1 ))

Any pointers, anyone?