entr

# entr (Event Notify Test Runner) A utility for running arbitrary commands when files change. ## Usage `entr` takes a list of filenames from standard input and executes the utility specified as the first argument. ### Syntax ```bash <file_listing_command> | entr <utility> [arguments] ``` ### Options - `-c`: Clear the screen before invoking the utility. - `-r`: Reload a persistent child process (e.g., a server). - `-s`: Evaluate the first argument using the interpreter specified by `SHELL`. ## Examples **Rebuild project when sources change:** ```bash find src/ -name "*.c" | entr make ``` **Run tests when JS files change:** ```bash git ls-files | grep '\.js$' | entr npm test ``` **Auto-reload a Node server:** ```bash ls *.js | entr -r node app.js ``` ## Agent Notes `entr` blocks the terminal. When using it as an agent: 1. Use `process` tool to run it in the background if you need to do other things. 2. Or use it for a quick "watch mode" session where you intend to monitor output for a while.