A common problem with Emacs is that the Del or Backspace key does not delete the character before the cursor, as it should, but instead invokes a help prompt. This problem is caused by an incompatible terminal setup file. A fairly robust fix is to create a file named .emacs in your home directory (or edit one that’s already there) and add the following lines:
(keyboard-translate ?\C-h ?\C-?) (keyboard-translate ?\C-\\ ?\C-h)
Now the Del or Backspace kill should work, and you can invoke help by pressing C-\ (an arbitrarily chosen key sequence).
Another potential problem is that on some systems, C-s causes the terminal to hang. This is due to an old-fashioned handshake protocol between the terminal and the system. You can restart the terminal by pressing C-q, but that doesn’t help you enter commands that contain the sequence C-s. The solution (aside from using a more modern dial-in protocol) is to create new key bindings that replace C-s or to enter those commands as M-x command-name. This is not specifically an Emacs problem, but it can cause problems when you run Emacs in a terminal window because C-s and C-q are commonly used Emacs key sequences.