The file etc-shadow
/etc/shadow is a file readable only by root and users with root privileges and contains the encrypted passwords of the users, each on a separate line:
frank:$6$i9gjM4Md4MuelZCd$7jJa8Cd2bbADFH4dwtfvTvJLOYCCCBf/.jYbK1IMYx7Wh4fErXcc2xQVU2N1gb97yI YaiqH.jjJammzof2Jfr/:18029:0:99999:7:::
Each line consists of nine colon-delimited fields:
| Fields | Description |
|---|---|
Username |
The name used when user logs into the system. |
Encrypted password |
The encrypted password of the user (if the value is !, the account is locked). |
Date of last password change |
The date of the last password change, as number of days since 01/01/1970. A value of 0 means that the user must change the password at the next access. |
Minimum password age |
The minimum number of days, after a password change, which must pass before the user will be allowed to change the password again. |
Maximum password age |
The maximum number of days that must pass before a password change is required. |
Password warning period |
The number of days, before the password expires, during which the user is warned that the password must be changed. |
Password inactivity period |
The number of days after a password expires during which the user should update the password. After this period, if the user does not change the password, the account will be disabled. |
Account expiration date |
The date, as number of days since 01/01/1970, in which the user account will be disabled. An empty field means that the user account will never expire. |
A reserved field |
A field that is reserved for future use. |