watchexec/cli

Watchexec CLI

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 Linux, Mac, Windows, and more

• Monitors current directory and all subdirectories for changes

  • Uses efficient event polling mechanism (on Linux, Mac, Windows, BSD)

• Coalesces multiple filesystem events into one, for editors that use swap/backup files during saving

• By default, uses .gitignore, .ignore, and other such files 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

• Launches the command in a new process group (can be disabled with --no-process-group)

• Optionally clears screen between executions

• Optionally restarts the command with every modification (good for servers)

• Optionally sends a desktop notification on command start and end

• Does not require a language runtime

• Sets the following environment variables in the process:

  $WATCHEXEC_COMMON_PATH is set to the longest common path of all of the below variables, and so should be prepended to each path to obtain the full/real path.

  Variable name	Event kind
  $WATCHEXEC_CREATED_PATH	files/folders were created
  $WATCHEXEC_REMOVED_PATH	files/folders were removed
  $WATCHEXEC_RENAMED_PATH	files/folders were renamed
  $WATCHEXEC_WRITTEN_PATH	files/folders were modified
  $WATCHEXEC_META_CHANGED_PATH	files/folders' metadata were modified
  $WATCHEXEC_OTHERWISE_CHANGED_PATH	every other kind of event

  These variables may contain multiple paths: these are separated by the platform's path separator, as with the PATH system environment variable. On Unix that is :, and on Windows ;. Within each variable, paths are deduplicated and sorted in binary order (i.e. neither Unicode nor locale aware).

  This can be disabled or limited with --no-environment (doesn't set any of these variables) and --no-meta (ignores metadata changes).

Anti-Features

• Not tied to any particular language or ecosystem
• Not tied to Git or the presence of a repository/project
• 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 command:

$ watchexec -r -s SIGKILL my_server

Send a SIGHUP to the command upon changes (Note: using -n 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

Run bundle install when the Gemfile changes:

$ watchexec -w Gemfile bundle install

Run two commands:

$ watchexec 'date; make'

If you come from entr, note that the watchexec command is run in a shell by default. You can use -n or --shell=none to not do that:

$ watchexec -n -- echo ';' lorem ipsum

On Windows, you may prefer to use Powershell:

$ watchexec --shell=powershell -- test-connection localhost

Installation

First-party

Pre-built

Use the download section on the website to obtain the package appropriate for your platform and architecture, extract it, and place it in your PATH.

There are also Debian/Ubuntu (DEB) and Fedora/RedHat (RPM) packages.

Checksums and signatures are available.

Cargo (from source)

Requires Rust 1.58.0 or later.

$ cargo install watchexec-cli

Binstall

$ cargo binstall watchexec-cli

Third-party

These are provided by third parties, caveat emptor!

macOS

• Homebrew: $ brew install watchexec
• Nix/NixOS: $ nix-env -iA nixpkgs.watchexec
• Webi: $ curl -sS https://webinstall.dev/watchexec | bash

Linux

• ArchLinux: $ pacman -S watchexec
• Nix/NixOS: $ nix-env -iA nixpkgs.watchexec
• Webi: $ curl -sS https://webinstall.dev/watchexec | bash

Windows

• Scoop: #> scoop install watchexec
• Chocolatey: #> choco install watchexec
• Webi: #> curl.exe -A MS https://webinstall.dev/watchexec | powershell

Shell completions

Currently available shell completions:

• zsh: completions/zsh should be installed to /usr/share/zsh/site-functions/_watchexec