Can not use command telnet in git bash
To add on to @lostbard's answer and @signonsridhar's comment, telnet utility need to be invoked with winpty to work on git bash.
Example:
MINGW64 ~
$ which telnet
/c/WINDOWS/system32/telnet
MINGW64 ~
$ winpty telnet localhost 2181
Zookeeper version: 3.4.14-4c25d480e66aadd371de8bd2fd8da255ac140bcf, built on 03/06/2019 16:18 GMT
That's because telnet is not provided with git.
In windows, you need to go to control panel, programs, turn windows features on/off and enable the telnet client.