lastupdate Specifies the time (in seconds) since the epoch (00:00:00 GMT, January 1, 1970) when the password was last changed. If password aging (the minage attribute or the maxage attribute) is in effect, the lastupdate attribute forces a password change when the time limit expires. (See the /etc/security/user file for information on password aging.) The passwd and pwdadm commands normally set this attribute when a password is changed. The value is a decimal integer that can be converted to a text string using the ctime subroutine.