Don't store specific commands in history

To force bash not to save duplicate commands, edit .bash_profile that is located in your home directory:

vi ~/.bash_profile
export HISTCONTROL=ignoredups

To force bash not to save lines that start with a space, edit .bash_profile that is located in your home directory:

vi ~/.bash_profile
export HISTCONTROL=ignorespace

To force bash not to save both(space and duplicates), edit .bash_profile that is located in your home directory:

vi ~/.bash_profile
export HISTCONTROL=ignoreboth