An absolute path is required, at least under windows. You can do something like bitcoin.exe -datadir="%cd%"
Here is my current batch file for starting bitcoin:
for /f "tokens=1,2*" %%a in ( 'nslookup %known-peer-address%' ) do (
if [%%a]==[Address:] set address=%%b
start bitcoin.exe -addnode=%address% -gen -datadir="%cd%\data"
Something similar could be done more elegant in linux.
As demonstrated here by riX, it is
possible to run Bitcoin standalone or "portable", on a USB thumb drive.
It is possible to have that USB thumb drive encrypted. Ofcourse it doesn't have to be a thumb drive but can be an external harddrive too!
It just requires some batch scripting, maybe we should release a batchscript with it called "standalone.bat" which will use -datadir=./.bitcoin and thus search for it on the USB thumb drive?