xenvflags

xenvflags is an utility that wrap around cli programs and automatically apply extra argument from environment variables. It is best used together with direnv.

Installation

# with homebrew
$ brew install favadi/xenvflags/xenvflags

# with go
$ go get github.com/favadi/xenvflags

Or download the pre-built binaries in releases section.

Example usages

For example, we are using shfmt for both personal and work projects.

• personal projects at ~/code/personal use 4 spaces indentation (arguments: -i 4)
• work projects are at ~/code/work use use 2 spaces indentation (arguments: -i 2)

The shfmt cli program is installed in /usr/local/bin/shfmt.

Setup:

• create a symlink to xenvflags: ln -s /usr/local/bin/xenvflags $HOME/bin/shfmt
• append SHFMT_EXTRA_ARGS='-i 4' to ~/code/personal/.envrc
• append SHFMT_EXTRA_ARGS='-i 2' to ~/code/work/.envrc

With direnv hook enabled, running shfmt in personal and work projects will have the desired indentation flags append.

Debug

# print xenvflags version and exit
$ XENVFLAGS_VERSION=true shfmt
dev

# print debug information
$ SHFMT_EXTRA_ARGS="-i 2" XENVFLAGS_DEBUG=true shfmt --help
2022/10/23 16:40:36 version: dev
2022/10/23 16:40:36 executable: /usr/local/bin/shfmt
2022/10/23 16:40:36 original arguments: [--help]
2022/10/23 16:40:36 extra arguments from env: [-i 2]
...