Checkexec

checkexec is a tool to conditionally execute commands only when files in a dependency list have been updated.

This tool provides the behavior of make as a standalone executable, where a command is only run if any of its dependencies have been updated. Like make, checkexec runs a command only if the modified time of any dependency is newer than the modified time of the target.

Usage

The arguments are: <target> <dependencies...> -- <command>. The -- is a required separator.

checkexec build/my-bin src/my-program.c -- cc -o build/my-bin src/my-program.c

checkexec executes the command directly, so shell constructs like '&&' and '||' are not supported. You can use /bin/bash -c as the command, but escaping is tricky. You're likely better off using two invocations of checkexec.

You can infer the dependency list with --infer, where checkexec will inspect the arguments of <command> for accessible paths. --infer will fail if no files are found.

checkexec build/my-bin --infer -- cc -o build/my-bin src/my-program.c

Installation

cargo install checkexec

Usage Notes

checkexec is great for when you build files from other files. Instead of relying on ecosystem-specific tools, you can use checkexec as part of any build tool. Here are some examples:

• You build, resize, or sample images as part of your build command, but don't want to rebuild them unless needed.
• You build C libaries as part of your Python, Rust, Node (or any other) build process.
• You build Sass/Less/SCSS files and don't want to re-build them unnecessarily.

checkexec pairs well with these tools:

• just fixes numerous problems with make, and checkexec adds back the conditional rebuild functionality of make. Together, they create a modular and modern build process and command runner.
• watchexec provides live reloading/rebuilding, while checkexec has callable behavior, useful as a build step or on CI. The naming similarity is intentional.
• fd makes it easy to specify a dependency file list. Example here:

# Only run your command if a rust file has changed. Note cargo does approximately the 
# same thing natively, but you can easily tailor this structure to a custom case.
checkexec target/debug/hello $(fd -e rs . src) -- cargo build

Exit codes

checkexec exit codes behave as you would expect, specifically:

• 0 (success) if the command is not run (i.e. target is up to date)
• 1 if a provided dependency or the command is not found
• Otherwise, when the command is run, checkexec will pass through the command's exit code.

Contributing

Contributions are what make the open source community such an amazing place to learn, inspire, and create. Any contributions you make are greatly appreciated.

If you have a suggestion that would make this better, please fork the repo and create a pull request. You can also simply open an issue with the tag "enhancement". Don't forget to give the project a star!

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