Note: If using automysqlbackup to backup all your MySQL databases on a Linux host, and you are getting the error:
ERROR 1045 (28000): Access denied for user ‘automysqlbackup’@’localhost’ (using password: YES)
even though you test it on the command line and can successfully login as the automysqlbackup user (or whichever user you are using for backups), make certain that the password for that user (‘automysqlbackup’ in my case) does not have any shell metacharacters, such as # or $, etc., or find the proper way to quote the password in the configuration file for automysqlbackup. (perhaps it is single quotes, perhaps double quotes…I did not test it, as I was “on the clock”, per se, and just removed the shell metacharacters from my password.)
See these two posts for more information: