as seen at my pal Philipp, I also wanted to see the current battery power in the bash prompt. So here is a script which works fine on my X60s.
REMAIN=`grep "remaining capacity" /proc/acpi/battery/BAT0/state | sed 's/remaining capacity:\(.*\)mWh/\1/'`
FULL=`grep "last full capacity" /proc/acpi/battery/BAT0/info | sed 's/last full capacity:\(.*\)mWh/\1/'`
echo $[ $REMAIN * 100 / $FULL ]
Just save it for example in your home directory as bat.sh and make it executable with ‚chmod +x bat.sh‘. Then edit the .bashrc file in your home dir and add the following line at the end:
PS1='[`~/bat.sh`%] \W> '
The \W is some preference from me, to see only the directory I’m currently in and not the whole path.