just.sh

just.sh transpiles Justfiles to portable, POSIX-compatible shell scripts.

• Run Justfile recipes without installing just
• Run just commands in constrained environments (such as CI pipelines and Docker containers)
• Use a justfile as a starting point for a shell script

just.sh is built as a drop-in replacement for just. It can parse any valid justfile, and generated scripts behave identically to just. In almost all cases, generated scripts even have byte-for-byte identical output to just. There are over 32,000 tests (covering every line of code!) that validate this compatibility for each commit.

Install & Quick Start

Try just.sh online without installing.

Install just.sh locally with:

python3 -m pip install just.sh

Once installed, run just.sh to convert a Justfile to a shell script. Then, run the generated script ./just.sh as you would run just.

$ ls
justfile

$ just --summary
build lint test

$ just.sh
Compiling Justfile to shell script: `justfile` -> `just.sh`

$ ls
justfile just.sh

$ ./just.sh --summary
build lint test

The pip installation script also installs the following aliases to the just.sh command-line tool:

• just_sh
• just-sh
• pyjust

Project Status

I like tools that effectively achieve one well-defined goal, without growing indefinitely. My hope is for just.sh to be such a tool.

In other words, just.sh is "complete" software. I will fix bugs and make changes to maintain compatibility with just, but there are no new features planned.

As such, even if there are no recent commits, the project is not dead! Few commits means that everything has been running smoothly.

just.sh is written in Python with only one dependency outside the Python standard library: parsy, which itself has no external dependencies. All of the code is spread across two fairly small files (plus one more for tests), and every line of code is covered by tests.

Known Issues & Incompatibilities

• Not all Just functions are implemented in shell
  • For example, many of the string manipulation functions such as trim_end_match, trim_start_match, titlecase, etc. remain to be implemented
  • Trying to compile a Justfile with an unimplemented function will raise an error
• Some Just functions (sha256 in particular) cannot be made portable without depending on sha256sum or Python on the target system
• Not all nested calls to just are detected. Calling just in the middle of a recipe may result in unexpected behavior
• 100% Python line coverage guarantees that all Python code that generates shell scripts is exercised, but it does not guarantee that all generated lines of shell are exercised in tests
• Just re-runs recipes if they are called again with a unique combination of arguments. just.sh approximates this behavior instead of replicating it, using simpler heuristics for whether a recipe has run before
• Generated just.sh shell files may be hard to read, and are typically much larger than the Justfiles they replace
• import, [confirm], and possibly some other recent features from Just versions greater than 1.14.0 may not yet be supported
• The ./just.sh --dump command does not reformat Justfiles
• The tests check colorless output of just.sh against just. They do not confirm that the colors and ANSI escape sequences are the same between the two

Acknowledgments

• Thanks to Logan Snow for testing early versions, consulting on design decisions, and being a great guy overall