What is that?

:%s/^M//g

To enter ^M, type CTRL-V, then CTRL-M. That is, hold down the CTRL key then press V and M in succession.

And what is this?

cp `ls -l *eps | grep "Nov 25" | cut -c55-80` nov25

Have no idea? Then need to take Unix course!

ls -l | egrep '^d' only directories

emacs

Gdb