Sometimes command line programs allow you to pass passwords to switches. For
example, MySQL: mysql -u user -p password. However, if your shell records
history, you’re risking to store your password in a plain text file. There’s a
way to avoid this. Depending on your shell add the following line.
Zsh
# ~/.zshrc
setopt HIST_IGNORE_SPACE
Bash
# ~/.bashrc
HISTCONTROL=ignorespace
Result
Now you can prepend a space character before your command. Such a command won’t be stored in your history.
% whoami
linuxhacker
% mysql -u user -p password
% # do your business... exit MySQL
% Bye.
Press Arrow_Up. The MySQL command isn’t in your history.
% ↑
% whoami