If you want to delete your bash history, there are a few options you have. First you must understand that the history of your bash session is stored into RAM and then written to ~/.bash_history when you log out of the bash session. So even if you delete the ~/.bash_history file, your current bash session will still be written to history once you log out.
To delete the bash history for your current session as well as old sessions, you should do two things:
Delete the .bash_history file:
# rm -rf ~/.bash_history
Clear the current history stored in RAM:
# history -c
Stop writing to .bash_history for good
If you don’t want to log any history for good, you can do one of two things; turn it off for all users, or turn off logging history for a single user.
Turn off bash history for all users:
Append “unset HISTFILE” to /etc/profile:
# echo "unset HISTFILE" >> /etc/profile
Turn off bash history for a specific user:
Append “unset HISTFILE” to /home/USER/.bash_profile:
# echo "unset HISTFILE" >> /home/USER/.bash_profile