Tmux

Tmux is the substitution of GNU Screen that is easier to use and everything works as expected, with tab features that allow you to open "new" shells to run new programs, inside the same Tmux session.

By default Tmux use the sequece of Ctrl+b to access some extra option. For example: Ctrl+b+% will split the window with a vertical line, where the new split have already access to the Shell ready to use. In the other hand, Screen don't offer that possibility so easy. Fans of GNU Screen want to change Tmux sequence action in the configuration file ~/.tmux.conf to bind the sequence to ctrl+a+.

To create new tabs you do ctrl+b+c to switch between tabs you can use ctrl+b+n for the next tab in list or ctrl+b+p to switch to the previous one, or you can use ctrl+b+number to access directly to the number of the tab created by Tmux. Use ctrl+b+" to create a horizontal split, and if you are using Tmux within a Graphical interface like i3 or any other, you can resize each split using ctrl+b+(arrow) keys without releasing the ctrl key hit as much times you want to resize it as you wish, or just ctrl+b+(arrow) key, releasing the ctrl key to move between splits.

For example, I always use Tmux after login in with htop to monitor computer activity, live-server to have a local web server to see the results of this pages I create on this blog before uploading them, Vim to write some HTML code or simple text files, w3m to browse the web, Mutt to see my Emails, Calcurse to organize my agenda, irssi for the IRC, newsboat to read the news using RSS protocol and the Tig to see changes inside Git repositories.

You can use Tmux to read manuals while testing your learning.

In a Minimal perspective, I could use a computer with 512MB of RAM and be able to use it without "delays", even if in my case, I use Firefox or Chromium to see the results just because I use colors and I cannot see them inside the shell. I don't know why Tmux don't have a dedicated page, but is OK. The repository already give you everything you need to know.