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.

USAGE

1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
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.

1
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.