man

When you use 'man xxxx' help, then press 'Q' key to quit.
It's something else with much space or pagedown.

nano

'nano' is a text editor. It is very useful. You can end to edit file with pressing F2 key. It is very light and simple.

repolist conf file about Debian.

nano /etc/apt/sources.list

In trouble, use Tab key. When you press Tab key twice time then get a proper path.

Do you know 'nano'? It is an application to edit. Have you already installed it?

multi boot GRUB

if you would change menu.lst to another. Type like this in GRUB menu.
X (or x-1) is the partition which has new menu.lst file.

root (hd0,x)
setup (hd0)

mount options

You shuld be careful to mount-options. Do you know 'uid, gid or defaults' ?
You can get a infomation from manual help.
Type 'man mount' or 'man fstab'. And check one which you search for.

dd

(input file): if
(output file): of

For Deleting on Linux system.

'-r' option is famous to use 'rm' command.
If you want delete some files, input '(sudo) rm -r' before name of files and folders.
But it cannot undo, are you ok?