The value of mindaysis the minimum number of days between password changes. A value of zero for this field indicates that the user may change her password at any time.
The value of maxdaysis the maximum number of days during which a password is valid. When maxdaysplus lastdayis less than the current day, the user will be required to change her password before being able to use her account.
The value of lastdayis the number of days since January 1st, 1970 when the password was last changed.
All of the above values are stored exactly as days when the shadow password file is used, but are converted to and from weeks when the standard password file is used. Because of this conversion, rounding errors may result.
If none of the options are selected, chageoperates in an interactive fashion, prompting the user with the current values for all of the fields. Enter the new value to change the field, or leave the line blank to use the current value. The current value is displayed between a pair of [ ]marks.