Provided by: passwd_4.0.13-7ubuntu3_i386
pwck - verify integrity of password files
pwck [-q] [-s] [passwd shadow]
pwck [-r] [passwd shadow]
pwck verifies the integrity of the system authentication information.
All entries in the /etc/passwd and /etc/shadow are checked to see that
the entry has the proper format and valid data in each field. The user
is prompted to delete entries that are improperly formatted or which
have other uncorrectable errors.
Checks are made to verify that each entry has:
· the correct number of fields
· a unique user name
· a valid user and group identifier
· a valid primary group
· a valid home directory
· a valid login shell
The checks for correct number of fields and unique user name are fatal.
If the entry has the wrong number of fields, the user will be prompted
to delete the entire line. If the user does not answer affirmatively,
all further checks are bypassed. An entry with a duplicated user name
is prompted for deletion, but the remaining checks will still be made.
All other errors are warning and the user is encouraged to run the
usermod command to correct the error.
The commands which operate on the /etc/passwd file are not able to
alter corrupted or duplicated entries. pwck should be used in those
circumstances to remove the offending entry.
The options which apply to the pwck command are:
-q Report errors only. Using this option will not require an action
from the user.
-r Execute the pwck command in read-only mode.
-s Sort entries in /etc/passwd and /etc/shadow by UID.
By default, pwck operates on the files /etc/passwd and /etc/shadow. The
user may select alternate files with the passwd and shadow parameters.
group account information
user account information
secure user account information
group(5), passwd(5), shadow(5), usermod(8).
The pwck command exits with the following values:
1 invalid command syntax
2 one or more bad password entries
3 can’t open password files
4 can’t lock password files
5 can’t update password files
Julianne Frances Haugh (firstname.lastname@example.org)