Added "ctrl-l" command that I use everyday

README.md

@@ -55,6 +55,8 @@ Scope:
 
 - In Bash, use **ctrl-r** to search through command history.
 
+- In Bash, use **ctrl-l** to clear the screen.
+
 - In Bash, use **ctrl-w** to delete the last word, and **ctrl-u** to delete the whole line. Use **alt-b** and **alt-f** to move by word, and **ctrl-k** to kill to the end of the line. See `man readline` for all the default keybindings in Bash. There are a lot. For example **alt-.** cycles through previous arguments, and **alt-*** expands a glob.
 
 - To go back to the previous working directory: `cd -`