Here are some commands for SQL*Plus that I found recently and hope it helps someone that, just like me, got frustrated having to retype EVERYTHING when you make a spelling error.
Just type in these commands at the SQL*Plus command prompt ( SQL> )
LIST - Displays the current buffer
DEL - Deletes the last line from the buffer
INPUT - Adds a new line to the current buffer ( Add the new line after INPUT e.g. INPUT where salary > 500 )
EDIT - Edits your current buffer in a text editor and returns it when you save and exit
RUN - Executes the current SQL statement in the buffer