watchexec

watchexec is a simple, standalone program that watches a path for changes and runs a command when it detects any modifications.

Features

• simple invocation and use
• monitors one or more root directories recursively for changes
• support watching only files with specific file extensions
• automatically uses ignores from .gitignore
  • if it doesn't exists then default ignores are used if not instructed to do otherwise
• optionally send a desktop notification with the exit code from the command
  • requires that the command notify-send is installed
• optionally clears the screen between executing the command
• optinally restart the command if it is already executing when a modification is detected
• optionally watch for metadata changes.
• sandbox feature which mean that when a process is terminated it also mean that all its children are killed
• sets the following environment variables in the child process when --env is used:
  • $WATCHEXEC_EVENT is a tuple of values "event type":"path"
  • If multiple files changed then the events are separated by ";"
• oneshot mode wherein watchexec compare the files on disk to a json database and only execute the command if the files have changed.

Usage Examples

A generic project that must first build the program before the test suite can execute.

$ watchexec -w src --shell -- "make all && make test"

If you are a D developer that wants to execute your tests.

$ watchexech -w source -- dub test

Getting Started

watchexec depends on the following software packages:

• D compiler (dmd 2.079+, ldc 1.11.0+)

It is recommended to install the D compiler by downloading it from the official distribution page.

# link https://dlang.org/download.html
curl -fsS https://dlang.org/install.sh | bash -s dmd

Then you can run watchexec via dub:

dub run watchexec

alternatively you can clone the repo and build it yourself.

git clone https://github.com/joakim-brannstrom/watchexec.git
cd watchexec
dub build -b release

Done! Have fun. Don't be shy to report any issue that you find.

Credit

This is a basically a re-implementation of watchexec. I had for a long time been using inotifywait in custom bash scripts but the rust version of watchexec where actually better.