ctrl-z.fish

Most TUI applications like nvim, hx and htop maps ctrl+z to send their process into the background and return to the shell prompt. To then bring the process back into the foreground you would use the fg command. While this is quick, it can be made more seamless by creating a fish keybind for ctrl+z to call fg. Allowing you to quickly toggle back and forth between the TUI program and the shell!

This functionality can be implemented in a single line:

bind \cz 'jobs --quiet && fg 2>/dev/null; commandline --function repaint'

So if this is enough functionality for you. You can simply copy the snippet into ~/.config/fish/config.fish

Beyond this, ctrl-z.fish provides two features in addition:

• A notification is printed to the terminal when you press ctrl+z and there are no jobs to bring to the foreground.
• A ctrl_z_to_bg event is emitted when you press ctrl+z in the TUI application and return to the shell prompt. This allows you to create listeners for this event that can be used to run commands when you return to the shell prompt. The rationale is that when you press ctrl+z you do it because you want to run a quick command in the shell, and then return to the TUI application. So why not automate this?
• If more than 1 job is in the background, an interactive picker is opened where you can select which job to bring into the foreground. Various metadata is shown for each job, such as its pgid, elapsed time or etime, and the cwd of the job. This information makes it easier to distinguish between similar background jobs, such as multiple open text editors instances.

Installation

fisher install kpbaks/ctrl-z.fish

Dependencies

• fzf used for the picker widget when there are >1 jobs in the background.

Usage

To use the ctrl_z_to_bg event, you need to create a listener for it. This can be done as follows:

# Run `cargo check` when you return to the shell prompt in a cargo project
function __ctrl-z.fish::listener::cargo_check --on-event ctrl_z_to_bg -a command
    test -f Cargo.toml; or return 0
    cargo check
end

# Run `git status --short` when you return to the shell prompt in a git repository
function __ctrl-z.fish::listener::git_status --on-event ctrl_z_to_bg -a command
    if command git rev-parse --is-inside-work-tree >/dev/null 2>&1
        command git status --short
    end
end

NOTE: The name of the listener function does not matter.

When the event is emitted, the command that was put into the background is passed as an argument to the listener function. You can use this to only run a command when a specific program is put into the background.

set -l EDITOR hx
$EDITOR README.md
# Press ctrl-z to return to the shell prompt
# Then the `-a command` argument will be expanded to `hx README.md`