Display hardware status in screen sessions

Afficher des informations sur le matériel de la machine (occupation CPU et mémoire) dans la ligne d’état de screen. Ça peut aider à diagnostiquer rapidement pourquoi la machine ne vous rend pas la main par exemple (est-elle occupée ou est-ce une panne réseau ?).

Screen can display a permanent status line with various informations. It might look like this (with various colors) :

 3 <hostname>               Load: 0,88 0,21 0,08  Mem: 1 / 3 G  2024-06-05 10:44

Here is how to get this :

$ vi ~/.screenrc

Add the following lines in the file (that might not exist before and can contain other useful settings) :

backtick 1 1 1 /bin/bash -c 'memLoad=$(free --giga | grep Mem | awk '\''{print $3" / "$2}'\''); echo "Mem: ${memLoad} G" ' (1)

hardstatus alwayslastline (2)
hardstatus string '%{wk} %n %H %=%{Yk} Load: %l %{Mk} %1` %{wk} %Y-%m-%d %c ' (3)

1	This creates a new replacement token for the status line definition. Here it’s a shell oneliner to extract the current RAM usage from the `free` command
2	Here we tell screen to display the status line, and to do it on the bottom of the `screen`.
3	Here we define what to display in the status line : `%{wk}` is a replacement token that adds the necessary terminal escape sequence to write in white text on black background `%n %H` is the buffer number in the screen session followed by the host name `%=` is an expendable white space `%{Yk}` changes the color of the next characters to bright yellow text on black background `%l` is the machine load averages %1` is the result of our `backtick` defined command … (read `man screen` for more escape sequences)

To test this settings you can start a new screen session or reload the settings of your current session via : CTRL+A : source ~/.screenrc

To finish, it exists at least screen-cpu-mem and rainbarf to create better backtick tokens for your status line with graphical levels or charts of CPU and memory usage.

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