Open terminal, gain root (you need 'rootsh', 'sudoer' or similar package, refer to it's documentation for 'how to gain root'). Then, write (again, as root!):

mv /path/to/bq27200.sh /usr/bin/

...and hit enter (of course, instead of /path/to/, write *real* path to file). File should be on place now - and You got new line to write in. So, write and execute:

chmod +x /usr/bin/bq27200.sh

...Now, You got everything set up. Now, just by writing and executing:

bq27200.sh

You got one-time dump of info regarding fuel gauge etc. Ho ever, if You execute:

bq27200.sh 5

...You will got "table" in terminal, showing most often used info, and refreshing it every 5 seconds. To stop it, You need to press ctrl+c on your N900 keyboard (just closing terminal will leave it running "invisible" in the background).

Ho ever, considering fact, that You got problems with basic terminal commands (no irony or offense here - You just need to learn this) I'm quite doubtful, that You'll be able to "parse" info you've got correctly. So, I strongly advise You using battery-eye or batterygraph. Those are GUI applications, you should have no problem using them.

Write here if You got any questions, or any conclusions. If You would just like to thanks - at some point - no need for separate post with that, just hit "thanks" button in right bottom corner of one's post.

Good luck!