bash: cls: command not found

Reason: This error indicates that either you have typed a wrong command or the command does not exist, to be honest, if you are on a UNIX operating system such as macOS this command is not a valid command, you should be using clear instead. cls is a clear screen command for Windows Command Prompt (MS-DOS)

Solution: You should use clear command instead! ✔️

Know more about clear command by typing help clear

$ clear help
Usage: clear [options]

Options:
  -T TERM     use this instead of $TERM
  -V          print curses-version
  -x          do not try to clear scrollback