Question about SHLVL

[justbispo]

I use starship as the prompt for my fish shell and I use a module that shows the value of the SHLVL environment variable, which shows how deeply nested . Whenever I start Ghostty, the value of this variable is 2. From the other terminal emulators I've tried, Alacritty and Wezterm are also 2, but Kitty is 1.
I've also tried with no configuration and the value is still the same.

The value being 1 or 2 bother me, I'm just curious if there's a specific reason why this happens, or if this isn't the expected behavior. From my limited knowledge, I can't think of a reason why Ghostty (and the other terminal emulators too) would use a nested shell.

[jcollie]

If you launch Ghostty from a shell that has SHLVL set, it will pass that environment variable to any shells that are subsequently launched. Each subshell will then increment the shell level.

[justbispo]

While I'm not launching Ghostty from a shell, your answer gave me a clue to find out why it happens. The application launcher (rofi in my case) is probably starting the programs in a subshell. When I launch the terminal with a window manager keybinding, the variable turns back to 1. And Kitty was the one still in that keybinding.