You shouldn't need the command line much, but if you want you perhaps freshen up your skills with the Introduction to the command line
book. You can read it online for free, download in various ebook formats for free, or buy the printed book. Anyway, most important of course is to have fun with Linux Mint
If you hadn't figured it you yet, you can mount your Android 4+ devices on Linux Mint also; http://www.webupd8.org/2012/12/how-to-m ... mtpfs.html
. Linux Mint being based on Ubuntu, you can use almost all programs and tutorials for Ubuntu on Linux Mint. Linux Mint 13 is based on Ubuntu 12.04 (should any tutorial refer to Ubuntu versions specifically).