Somebody posted a portable client, but I don't trust them, so I'll show you how to make your own.
Download the windows .zip from bitcoin.org
Unpack it. Go into that directory.
Make a file called
Put this in it:
start bitcoin-qt.exe -datadir=data
Rename it to
Make a folder called
It should look like this. Double-click
launch.bat to start it. If files show up in the data folder you made, then you've done things correctly.
Download the Mac .dmg from bitcoin.org
Find the Bitcoin-Qt.app file, and copy it to to your flash drive.
Go to Launchpad, type in 'terminal'. Hit enter.
When the terminal comes up, type:
nano start.sh; chmod +x start.sh
dir1=$(cd "$(dirname "$0")"; pwd)
dir=`echo $dir1 | sed 's/"/\\"/g' | tr -d '\n'`
Now hit Ctrl-O, enter, Ctrl-X. You should be back at the terminal.
Find the lines that look like this:
Change it to:
Now hit Ctrl-O, enter, Ctrl-X. You should be back at the terminal. Now we just need to give it a better name.
mv Bitcoin-Qt.app BitcoinPortable.app
Try running your BitcoinPortable.app. If you see files show up in the data directory next to it, then you've done things correctly!
Thanks to Pygy for the script
Note: I don't have a Mac, so this is untested.