Enable "vi mode" in your ksh shell and embrace the feeling of vi shortcuts:
echo "set -o vi" >> $HOME/.kshrc
In a new shell, you can navigate the history with Esc + j or k
Move the cursor in a long command with h or l
Search and filter the history with Esc + /
Vi lovers, see xcape to addxcape -e 'Alt_L=Escape' &
to your "$HOME/.xsession
" file.