StreamThe process.stdin property returns a stream connected to
stdin (fd 0). It is a net.Socket (which is a Duplex
stream) unless fd 0 refers to a file, in which case it is
a Readable stream.
For details of how to read from stdin see readable.read().
As a Duplex stream, process.stdin can also be used in "old" mode that
is compatible with scripts written for Node.js prior to v0.10.
For more information see Stream compatibility.
In "old" streams mode the stdin stream is paused by default, so one
must call process.stdin.resume() to read from it. Note also that calling
process.stdin.resume() itself would switch stream to "old" mode.
numberThis property refers to the value of underlying file descriptor of
process.stdin. The value is fixed at 0. In Worker threads,
this field does not exist.