Mini Project: Change the color of the terminal based on the time of day

Question

Good Evening,

I am pretty new to Unix so maybe this mini project is too ambitious. Hoping someone could point in in the right direction.

Working in a cubicle and I can't see how light it is outside. In general I use a yellow terminal in the morning (sunny) and a black/green past 3:00 (night).

What I would like to do (partly just to practice my bash). Is to write a script that will at 3:00 change the color of all of my terminals. If that works maybe I will make them change every hour or something like that. Would that be safe? Is this possible?

Here are some of my specs: Solaris 10 Bash shell Gnome

I am looking at this right now: Change Gnome terminal theme programmatically

Answer 1

If I were doing this, I'd start with PROMPT_COMMAND. Bash will run that script just before displaying a prompt.

You have a couple of choices. You could have a script itself inside PROMPT_COMMAND:

PROMPT_COMMAND='if [ is_morning ]; then echo "MORNING_COLORS'; else echo "EVENING_COLORS"; fi

Or you could have PROMPT_COMMAND run an external command (which could also be a bash script or you could use a different language if you wanted) to do all the work there:

PROMPT_COMMAND=/path/to/setcolor_timeofday

The only hole I see in this is that if you have a program running when the time changes over (for example, using tail -f to watch a file), the background won't change until you return to the bash prompt.

Answer 2

Modifying the shell foreground and background colors via PS1 in bash will be the easiest, as pointed out by others here. R Samuel Klatchko's approach with PROMPT_COMMAND is probably the most versatile. However, this has drawbacks. Bash can only use 'dull' background colors, and its foreground/background colors can be overridden by any application. Modifying your Gnome Terminal theme programmatically, especially in realtime, will be far harder, but produce much prettier results.