Can't be done. If it's corrupted, it's corrupted. The command line isn't magic. In fact, the graphical interface issues literally the same commands as the command line, it just makes it easier.
If you've got a flash drive that's corrupted and you absolutely must get data off it, you should take it to a data recovery specialist. It's not going to be cheap, but it's the only way I'll recommend recovering data like this. Trying to fix it yourself can make it impossible to recover, and if it's critical, don't take chances.
Also, don't keep critical data on only a single drive, especially a flash drive.