CasperSecurity
# 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
```javascript
const which = require('which')
// async usage
// rejects if not found
const resolved = await which('node')
// if nothrow option is used, returns null if not found
const resolvedOrNull = await which('node', { nothrow: true })
// sync usage
// throws if not found
const resolved = which.sync('node')
// if nothrow option is used, returns null if not found
const resolvedOrNull = which.sync('node', { nothrow: true })
// Pass options to override the PATH and PATHEXT environment vars.
await which('node', { path: someOtherPath, pathExt: somePathExt })
```
## CLI USAGE
Just like the BSD `which(1)` binary but using `node-which`.
```
usage: node-which [-as] program ...
```
You can learn more about why the binary is `node-which` and not `which`
[here](https://github.com/npm/node-which/pull/67)
## 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.