#watcher #filesystem #cli #watchexec

app watchexec-cli

Executes commands in response to file modifications

4 stable releases

1.17.0 Jul 21, 2021
1.16.2 Jul 10, 2021
1.16.1 May 22, 2021
1.16.0 May 8, 2021

#19 in Command line utilities

Download history 133/week @ 2021-05-06 100/week @ 2021-05-13 189/week @ 2021-05-20 103/week @ 2021-05-27 102/week @ 2021-06-03 122/week @ 2021-06-10 75/week @ 2021-06-17 87/week @ 2021-06-24 93/week @ 2021-07-01 393/week @ 2021-07-08 346/week @ 2021-07-15 348/week @ 2021-07-22

562 downloads per month

Apache-2.0

91KB
2K SLoC

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)
  • Coalesces multiple filesystem events into one, for editors that use swap/backup files during saving
  • By default, uses .gitignore and .ignore 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)
  • Sets the following environment variables in the 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
    • This can be disabled or limited with --no-environment and --no-meta
  • 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 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 1.43 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

Dependencies

~11MB
~206K SLoC