command-exists 1.2.9

Command-exists is a handy Node.js module whose primary function is to check if a particular command-line command exists in the current environment. This feature allows your Node.js applications to perform certain actions or change the flow of execution based on the availability of certain command-line tools.

You can install command-exists using npm:

npm install command-exists

You can then use it in three ways:

• Async mode: Invoking the commandExists function with a command and a callback function. The callback will be called with err and commandExists arguments, the latter being a boolean indicating the existence of the command.

  var commandExists = require('command-exists');
  commandExists('ls', function(err, commandExists) {
      if(commandExists) {
          // proceed confidently knowing this command is available
      }
  });
  

• Promise mode: If commandExists is invoked without a callback, it returns a promise that will be resolved with the command if exists, or rejected if it doesn't.

  var commandExists = require('command-exists');
  commandExists('ls')
  .then(function(command){
      // proceed
  }).catch(function(){
      // command doesn't exist
  });
  

• Sync mode: The commandExistsSync function synchronously checks the existence of a command and returns a boolean value.

  var commandExistsSync = require('command-exists').sync;
  if (commandExistsSync('ls')) {
      // proceed
  } else {
      // ...
  }
  

The most up-to-date and detailed documentation for command-exists can be found in the README file on its GitHub repository at the URL: https://github.com/mathisonian/command-exists. This readme file includes installation instructions, usage examples for all supported modes, and a chronological changelog with changes made in each version of the package.