How to write a custom command on linux

I want to create a custom command on linux (ubantu) which I need to execute regularly. steps are: create a shell-script place the shell script in /usr/bin/ dir name of shell-script file is custom command e.g I want kill node processes running by just typing “killnode” #!/bin/bash #fileName /usr/bin/killnode #echo "the folder is `pwd`" #echo