RFC: Remove the color prompt overrides from default instance and shell environment for v1.0?

[afbjorklund]

Description

We had an old issue, to make the lima prompt distinguishable from the host prompt.

The color was playing on the "lime" word game, and used a bright yellow-green (Lime)

Here the color(s) shown in Ubuntu terminal: 

---

But it requires 24-bit color support to look best, as an addition to 256 (or 16) colors support:

• https://github.com/lima-vm/lima/pull/433

• https://github.com/lima-vm/lima/pull/435

• COLORTERM=truecolor

And it doesn't really work on light backgrounds, so requires support for the terminal "theme":

• https://github.com/lima-vm/lima/issues/485

• https://github.com/lima-vm/lima/pull/486

• TERMTHEME=Dark

---

So I think the best would be to remove those changes, and go back to the original issue:

• https://github.com/lima-vm/lima/issues/427

Go back to the original Ubuntu prompt:

-if [ "$color_prompt" = yes ]; then
-    PS1='${debian_chroot:+($debian_chroot)}\[\033[01;32m\]\u@\h\[\033[00m\]:\[\033[01;34m\]\w\[\033[00m\]\$ '
+# Lima PS1: set color to lime
+if [ "$color_prompt" = true ]; then
+    PS1='${debian_chroot:+($debian_chroot)}\[\033[38;2;192;255;0m\]\u@\h\[\033[00m\]:\[\033[01;34m\]\w\[\033[00m\]\$ '
+elif [ "$color_prompt" = 256 ]; then
+    PS1='${debian_chroot:+($debian_chroot)}\[\033[38;5;154m\]\u@\h\[\033[00m\]:\[\033[01;34m\]\w\[\033[00m\]\$ '
+elif [ "$color_prompt" = yes ]; then
+    PS1='${debian_chroot:+($debian_chroot)}\[\033[01;92m\]\u@\h\[\033[00m\]:\[\033[01;34m\]\w\[\033[00m\]\$ '
 else
     PS1='${debian_chroot:+($debian_chroot)}\u@\h:\w\$ '
 fi

Note that the default prompt does have the host name in it, which does include "lima":

anders@lima-default:/home/anders$ uname
Linux

But it could be desired to change the prompt?

[ "$PS1" ] && PS1="[LIMA] $PS1"

[afbjorklund]

A compromise, if wanting to keep the color override, would be to go for "lime green"

• #C0FF00 (xterm-256color: GreenYellow # 154)
• #32CD32 (xterm-256color: PaleGreen3 # 77)

It's not great on a light background, but you can at least make out the characters...

• https://coolors.co/contrast-checker/c0ff00-ffffff (1.20)
• https://coolors.co/contrast-checker/32cd32-ffffff (2.12)

---

This makes it work also with the "light" themes, here showing base16-shell "default":

[afbjorklund]

Two issues:

• Remove the export of the COLORTERM variable ? It is available on the host, but not (normally) over ssh connections. It complicates the ssh setup a bit, have to send it from the client and also accept it on the host. But it is "generic".

cmd/limactl/shell.go:   if _, present := os.LookupEnv("COLORTERM"); present {
cmd/limactl/shell.go:           sshArgs = append(sshArgs, "-o", "SendEnv=\"COLORTERM\"")

# accept any incoming COLORTERM environment variable
sed -i 's/^AcceptEnv LANG LC_\*$/AcceptEnv COLORTERM LANG LC_*/' /etc/ssh/sshd_config

• Remove the change of color in the "default" instance. Note that "ubuntu" (without nerdctl) does not get patched... After the latest change, it will only change the default green prompt to a slightly more lime green on color terminals.

After that:

• Should the limactl shell change the PS1, similar to what Singularity/Apptainer does ? (Docker/Podman does not)

• Or should we rely on the user shell configuration to pick up the presence of SSH_CLIENT, like Powerline does?

[AkihiroSuda]

I guess we can just remove the custom PS1

[afbjorklund]

I'm seeing lime green color everywhere, so think I will just keep it as it is now.