README.md
1# which
2
3Like the unix `which` utility.
4
5Finds the first instance of a specified executable in the PATH
6environment variable. Does not cache the results, so `hash -r` is not
7needed when the PATH changes.
8
9## USAGE
10
11```javascript
12var which = require('which')
13
14// async usage
15which('node', function (er, resolvedPath) {
16 // er is returned if no "node" is found on the PATH
17 // if it is found, then the absolute path to the exec is returned
18})
19
20// sync usage
21// throws if not found
22var resolved = which.sync('node')
23
24// if nothrow option is used, returns null if not found
25resolved = which.sync('node', {nothrow: true})
26
27// Pass options to override the PATH and PATHEXT environment vars.
28which('node', { path: someOtherPath }, function (er, resolved) {
29 if (er)
30 throw er
31 console.log('found at %j', resolved)
32})
33```
34
35## CLI USAGE
36
37Same as the BSD `which(1)` binary.
38
39```
40usage: which [-as] program ...
41```
42
43## OPTIONS
44
45You may pass an options object as the second argument.
46
47- `path`: Use instead of the `PATH` environment variable.
48- `pathExt`: Use instead of the `PATHEXT` environment variable.
49- `all`: Return all matches, instead of just the first one. Note that
50 this means the function returns an array of strings instead of a
51 single string.
52