6.4 Keeping your password secure

It is inadvisable to specify your password in a way that exposes it to discovery by other users. The methods you can use to specify your password when you run client programs are listed below, along with an assessment of the risks of each method:

• Use a -pyour_pass or --password=your_pass option on the command line. This is convenient but insecure, since your password becomes visible to system status programs (such as ps) that may be invoked by other users to display command lines. (MySQL clients typically overwrite the command line argument with zeroes during their initialization sequence, but there is still a brief interval during which the value is visible.)
• Use a -p or --password option (with no your_pass value specified). In this case, the client program solicits the password from the terminal:

  shell> mysql -u user_name -p
  Enter password: ********
  

  The client echoes `*' characters to the terminal as you enter your password so that onlookers cannot see it. It is more secure to enter your password this way than to specify it on the command line because it is not visible to other users. However, this method of entering a password is suitable only for programs that you run interactively. If you want to invoke a client from a script that runs non-interactively, there is no opportunity to enter the password from the terminal.
• Store your password in a configuration file. For example, you can list your password in the [client] section of the `.my.cnf' file in your home directory:

  [client]
  password=your_pass
  

  If you store your password in `.my.cnf', the file should not be group or world readable or writable. Make sure the file's access mode is 400 or 600. 4.15.4 Option files.
• You can store your password in the MYSQL_PWD environment variable, but this method must be considered extremely insecure and should not be used. Some versions of ps include an option to display the environment of running processes; your password will be in plain sight for all to see if you set MYSQL_PWD. Even on systems without such a version of ps, it is unwise to assume there is no other method to observe process environments.

All in all, the safest methods are to have the client program prompt for the password or to specify the password in a properly-protected `.my.cnf' file.