/etc/shadow file
root:$6$EA9l7lWI$1KXpR1dYwKe0icL0ohivqdyPdwzcxn0FuH.:16856:0:99999:7:::
Username, up to 8 characters. Case-sensitive, usually all lowercase. A
direct match to the username in the /etc/passwd file.
Password, encrypted.
The number of days since January 1, 1970 since the password was last changed.
The number of days before password may be changed (0 indicates it may be changed at any time)
The number of days after which password must be changed (99999 indicates user can keep his or her password unchanged for many, many years)
The number of days to warn user of an expiring password (7 for a full week)
The number of days after password expires, but can be used. Account will be disabled if pwd is not changed.
The number of days since January 1, 1970 when an account will be disabled
A reserved field for possible future use