Zsh: using color
Zsh color nonsense
This is a fairly random collection of notes to myself about using color in Zsh shell scripts.
Maybe you will find them useful.
Using colors in Scripts
Zsh ships with a cunningly named function named colors. It is a common function used in zsh scripts.
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autoload -Uz colors && colors |
It defines several associative arrays and variables.
The “main” arrays are color and its alias colour.
The arrays you actually use are fg, fg_bold, and fg_no_bold for the foregound and
bg, bg_bold, and bg_no_bold for the background.
Here is how to print a message in a particular color, bold red in this case.
The array indexes are keys from the color/colour array. reset_color does what it
says on the tin. Leave it out and see what happens 🙂
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print -- $fg_bold[red]enter filename$reset_color |
This will show the keys.
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for k in ${color} do print -- key: $k done |
This might help seeing the relationships. 31 is the standard ANSI code for red.
color/colours holds these values and more.
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print -- $fg[$color[31]]foo$reset_color <br /># which is the same as <br />print -- $fg[red]foo$reset_color |
That 31 for red would be inserted into the ANSI escape code “ESC[31m”.
The array fg (and friends) holds these ANSI code values. If you don’t believe me, try this script.
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for k in ${fg} do     print -- key: $k done |
key: ESC[32m
key: ESC[36m
key: ESC[37m
key: ESC[33m
key: ESC[35m
key: ESC[30m
key: ESC[34m
key: ESC[31m
key: ESC[39m
key: ESC[30m
key: ESC[32m
Besides print, you can use color elsewhere. For example, here is a read snippet.
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read -qs "answer?$fg_bold[green]$bg[blue]Do the thing? [yn] $reset_color" print ${answer} # probably use a case statement on $answer |
Other attributes such as underline and blink are there, but they don’t work with
iTerm on macOS. For flakily supported things like this its better to avoid them.
Shell prompt color
The prompt syntax is a bit different. You can use it with print via the -P flag
if you want to test your prompt, or if you just like using its baroque syntax.
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print -P -- "%F{red}%K{bg-blue}test string%k%f" |
There are 1.6022 x 10^23 tutorials out there on customizing the zsh prompt, so
“that’s all I have to say about that”.
ps
I just use Powerlevel10k to customize my prompt. If I’m in need of distraction, I’ll just edit my Emacs LISP instead of treading the zsh “theme” path.
