Screen Mode for VT Terminals
Screen mode differs from Visual mode by doing edits to a line right away, instead of waiting for a screenful of changes. Use PF1 for Help, PF3/PF4 to browse back and forth in the file. You can enter new text right away (there is no concept of command mode vs insert mode like there is in vi). Perform edit operations with control-key sequences. To exit Screen mode, press ^E.