• Distrobox
  • Execute a command on the host
    • With distrobox-host-exec
    • Using symlinks
  • Integrate host with container seamlessly
    • bash or zsh
    • fish

Execute a command on the host

It may be needed to execute commands back on the host. Be it the filemanager, an archive manager, a container manager and so on.

Here are a couple of solutions.

With distrobox-host-exec

distrobox offers the distrobox-host-exec helper, that can be used exactly for this.

See distrobox-host-exec.

user@fedora-distrobox:~$ which podman
/usr/bin/which: no podman in [...]
user@fedora-distrobox:~$ distrobox-host-exec podman version # <-- this is executed on host.
Client:
Version:      3.4.2
API Version:  3.4.2
Go Version:   go1.16.6
Built:        Thu Jan  1 01:00:00 1970
OS/Arch:      linux/amd64

Server:
Version:      3.4.2
API Version:  3.4.2
Go Version:   go1.16.6
Built:        Thu Jan  1 01:00:00 1970
OS/Arch:      linux/amd64

Using symlinks

Another way to execute commands on the host, is to create executables symlinking distrobox-host-exec:

user@fedora-distrobox:~$ ln -s /usr/bin/distrobox-host-exec /usr/local/bin/podman
user@fedora-distrobox:~$ ls -l /usr/local/bin/podman
lrwxrwxrwx. 1 root root 51 Jul 11 19:26 /usr/local/bin/podman -> /usr/bin/distrobox-host-exec
user@fedora-distrobox:~$ podman version # <-- this is executed on host. Equivalent to "distrobox-host-exec podman version"
Client:
Version:      3.4.2
API Version:  3.4.2
Go Version:   go1.16.6
Built:        Thu Jan  1 01:00:00 1970
OS/Arch:      linux/amd64

Server:
Version:      3.4.2
API Version:  3.4.2
Go Version:   go1.16.6
Built:        Thu Jan  1 01:00:00 1970
OS/Arch:      linux/amd64

Integrate host with container seamlessly

Another cool trick we can pull, is to use the handy command_not_found_handle function to try and execute missing commands in the container on the host.

bash or zsh

Place this in your ~/.profile:

command_not_found_handle() {
# don't run if not in a container
  if [ ! -e /run/.containerenv ] && [ ! -e /.dockerenv ]; then
    exit 127
  fi
  
  distrobox-host-exec "${@}"
}
if [ -n "${ZSH_VERSION-}" ]; then
  command_not_found_handler() {
    command_not_found_handle "$@"
 }
fi

And then, run source ~/.profile to reload .profile in the current session.

fish

Place this snippet in a new fish function file (~/.config/fish/functions/fish_command_not_found.fish):

function fish_command_not_found
    # "In a container" check
    if test -e /run/.containerenv -o -e /.dockerenv
        distrobox-host-exec $argv
    else
        __fish_default_command_not_found_handler $argv
    end
end

And restart your terminal. Now when a command does not exist on your container, it will be automatically executed back on the host:

user@fedora-distrobox:~$ which podman
/usr/bin/which: no podman in [...]
user@fedora-distrobox:~$ podman version # <-- this is automatically executed on host.
Client:
Version:      3.4.2
API Version:  3.4.2
Go Version:   go1.16.6
Built:        Thu Jan  1 01:00:00 1970
OS/Arch:      linux/amd64

Server:
Version:      3.4.2
API Version:  3.4.2
Go Version:   go1.16.6
Built:        Thu Jan  1 01:00:00 1970
OS/Arch:      linux/amd64

This is also useful to open code, xdg-open, or flatpak from within the container seamlessly.