[Feature]: argument `--env` to set environment variable

[knyipab]

Feature description

Continue the discussion of wrapping command (first mentioned in #409 ). There is currently no way to set environment variables for command such as R_HOME for proot-distro login ubuntu --work-dir="$PWD" -- R "$@".

You know, many programs uses environment variables as input. It looks good if we can use --env

• proot-distro login ubuntu --work-dir="$PWD" --env R_HOME="..." -- R "$@"
• proot-distro login ubuntu --work-dir="$PWD" --env R_HOME -- R "$@" to inherit host R_HOME

I do see the need of --env, just like -e in docker run. Termux users nowadays perhaps use proot-distro just like docker becuz the latter is not available.

By the way, I am well aware of alternative like eval or bash << docstring but escaping all $@ seems horrible.

[sylirre]

Available in next version

[knyipab]

Thanks!