GNU Screen

Recently, i came upon a problem when i was downloading the Debian 4.0 etch ISOs using jigdo. I couldn’t background the process and connection was getting closed when the session ended.

The solution was GNU Screen

The GNU Screen is essentially a windowing system for the console. They have a technical description for it in their site. But, this is what it does:

It can be used to create mutiple independent sessions. One can effectively switch between these sessions and the processess in these sessions keeps running even when you log out.

Gnu screen is available with the debian distro itself (don’t know about others as i use only debian).

When you type screen in the terminal, you will see its license information (GPL). A screen session is now created. Once within the screen, every screen command is prefixed by Ctrl+a combo.

Here is the list of the commands to type in the terminal and what they do:

screen - a screen session is attached.

Ctrl+a d - detaches from the session and if any process is running, it is run in the background. It returns where you were before typing screen. It also shows this- [screen detached].

screen -R - this command reattaches you with screen after you typed Ctrl+a d.

exit - Once within screen this command terminates screen and shows this in the output – [screen terminated]

You can create multiple separate shells within screen.

Ctrl+a c - this creates a new shell within screen.

Ctrl+a Ctrl+a - this is used to switch between sessions created as above.

Ctrl+a “ – this shows a list of sessions created by C-a c with a number (starting from 0) and a corresponding name.

Ctrl+a A - this command is used to rename the session.

Ctrl+a k - kills the current session.

Ctrl+a S - splits the current window. The new window is empty by default.

Ctrl+a TAB – used to switch between the split windows. You can use C-a C-a to have one of the already created sessions in the split window.

You can also use exit to close sessions.

This is my brief Howto on GNU Screen!!!