>In MS-DOS, you can type a command like "cd.." to move up a level, and it will work fine. In Linux, it will not; you need to type "cd ..". The different is the space in between. Similar examples abound; in MS-DOS, you can type "dir/p", without a space between the command and its switch. This is a big deal, even if it might not seem like it.
you can add those commands (as functions) to linux, but it would be a boneheaded thing to do.
cd.. () {
cd ..
}