# watchexec
[](https://travis-ci.org/watchexec/watchexec)
[](https://ci.appveyor.com/project/watchexec/watchexec)
[](https://crates.io/crates/watchexec)
Software development often involves running the same commands over and over. Boring!
`watchexec` is a **simple**, standalone tool that watches a path and runs a command whenever it detects modifications.
Example use cases:
* Automatically run unit tests
* Run linters/syntax checkers
## Features
* Simple invocation and use
* Runs on OS X, Linux and Windows
* Monitors current directory and all subdirectories for changes
* Uses most efficient event polling mechanism for your platform (except for [BSD](https://github.com/passcod/notify#todo))
* Coalesces multiple filesystem events into one, for editors that use swap/backup files during saving
* By default, uses `.gitignore` to determine which files to ignore notifications for
* Support for watching files with a specific extension
* Support for filtering/ignoring events based on [glob patterns](https://docs.rs/globset/*/globset/#syntax)
* Launches child processes in a new process group
* Sets the following environment variables in the child process:
* If a single file changed (depending on the event type):
* `$WATCHEXEC_CREATED_PATH`, the path of the file that was created
* `$WATCHEXEC_REMOVED_PATH`, the path of the file that was removed
* `$WATCHEXEC_RENAMED_PATH`, the path of the file that was renamed
* `$WATCHEXEC_WRITTEN_PATH`, the path of the file that was modified
* `$WATCHEXEC_META_CHANGED_PATH`, the path of the file whose metadata changed
* If multiple files changed:
* `$WATCHEXEC_COMMON_PATH`, the longest common path of all of the files that triggered a change
* Optionally clears screen between executions
* Optionally restarts the command with every modification (good for servers)
* Does not require a language runtime
## Anti-Features
* Not tied to any particular language or ecosystem
* Does not require a cryptic command line involving `xargs`
## Usage Examples
Watch all JavaScript, CSS and HTML files in the current directory and all subdirectories for changes, running `make` when a change is detected:
$ watchexec --exts js,css,html make
Call `make test` when any file changes in this directory/subdirectory, except for everything below `target`:
$ watchexec -i target make test
Call `ls -la` when any file changes in this directory/subdirectory:
$ watchexec -- ls -la
Call/restart `python server.py` when any Python file in the current directory (and all subdirectories) changes:
$ watchexec -e py -r python server.py
Call/restart `my_server` when any file in the current directory (and all subdirectories) changes, sending `SIGKILL` to stop the child process:
$ watchexec -r -s SIGKILL my_server
Send a SIGHUP to the child process upon changes (Note: with using `-n | --no-shell` here, we're executing `my_server` directly, instead of wrapping it in a shell:
$ watchexec -n -s SIGHUP my_server
Run `make` when any file changes, using the `.gitignore` file in the current directory to filter:
$ watchexec make
Run `make` when any file in `lib` or `src` changes:
$ watchexec -w lib -w src make
## Installation
### Cargo
watchexec requires Rust 1.26 or later. You can install it using cargo:
$ cargo install watchexec
### OS X with Homebrew
$ brew install watchexec
### Linux
For now, use the GitHub Releases tab to obtain the binary. PRs for packaging in unsupported distros are welcomed.
#### Debian
A deb package is available for amd64 architectures in the GitHub Releases.
#### Arch Linux
Available [on the AUR](https://aur.archlinux.org/packages/watchexec/):
$ yay -S watchexec
### Windows
Available [using scoop](https://scoop.sh/):
#> scoop install watchexec
Or just unzip the binary from the GitHub Releases.
## Building
Rust 1.26 or later is required.
## Credits
* [notify](https://github.com/passcod/notify) for doing most of the heavy-lifting
* [globset](https://crates.io/crates/globset) for super-fast glob matching