which

Like the unix which utility.

Finds the first instance of a specified executable in the PATH environment variable. Does not cache the results, so hash -r is not needed when the PATH changes.

Unlike the original version of this package, this does not look for the binary in the CWD on Windows. This is change was needed to avoid binary planting attacks.

USAGE

var which = require('which')

// async usage
which('node', function (er, resolvedPath) {
  // er is returned if no "node" is found on the PATH
  // if it is found, then the absolute path to the exec is returned
})

// or promise
which('node').then(resolvedPath => { ... }).catch(er => { ... not found ... })

// sync usage
// throws if not found
var resolved = which.sync('node')

// if nothrow option is used, returns null if not found
resolved = which.sync('node', {nothrow: true})

// Pass options to override the PATH and PATHEXT environment vars.
which('node', { path: someOtherPath }, function (er, resolved) {
  if (er)
    throw er
  console.log('found at %j', resolved)
})

CLI USAGE

Same as the BSD which(1) binary.

usage: which [-as] program ...

OPTIONS

You may pass an options object as the second argument.

• path: Use instead of the PATH environment variable.
• pathExt: Use instead of the PATHEXT environment variable.
• all: Return all matches, instead of just the first one. Note that this means the function returns an array of strings instead of a single string.