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.
var which = // async usage // sync usage // throws if not found var resolved = which // Pass options to override the PATH and PATHEXT environment vars. Same as the BSD which(1) binary.
usage: which [-as] program ...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.