I find the following Bash history settings invaluable and use them on every Ubuntu terminal I can.

When you use Ctrl+Shift+R in bash it searches in reverse through your previously run commands. These commands are usually stored in a .bash_history file, but only for a limited number of commands. These following instructions enable an unlimited history for all your previously run commands [source]:

First, you must comment out or remove this section of your .bashrc (default for Ubuntu). If you don’t, then certain environments (like running screen sessions) will still truncate your history:

# for setting history length see HISTSIZE and HISTFILESIZE in bash(1)

Second, add this to the bottom of your .bashrc:

# Eternal bash history.
# ---------------------
# Undocumented feature which sets the size to "unlimited".
# http://stackoverflow.com/questions/9457233/unlimited-bash-history
export HISTSIZE=
export HISTTIMEFORMAT="[%F %T] "
# Change the file location because certain bash sessions truncate .bash_history file upon close.
# http://superuser.com/questions/575479/bash-history-truncated-to-500-lines-on-each-login
export HISTFILE=~/.bash_eternal_history
# Force prompt to write history after every command.
# http://superuser.com/questions/20900/bash-history-loss

It gives you an unlimited bash history that also records the time the command was run and saves the command instantly instead of waiting till you exit your session.