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pwck(8) [linux man page]

PWCK(8) 						    System Management Commands							   PWCK(8)

NAME
pwck - verify integrity of password files SYNOPSIS
pwck [-q] [-s] [passwd [ shadow ]] pwck [-q] [-r] [passwd [ shadow ]] DESCRIPTION
The pwck command verifies the integrity of the users and authentication information. It checks that all entries in /etc/passwd and /etc/shadow have the proper format and contain valid data. 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: o the correct number of fields o a unique and valid user name o a valid user and group identifier o a valid primary group o a valid home directory o a valid login shell shadow checks are enabled when a second file parameter is specified or when /etc/shadow exists on the system. These checks are the following: o every passwd entry has a matching shadow entry, and every shadow entry has a matching passwd entry o passwords are specified in the shadowed file o shadow entries have the correct number of fields o shadow entries are unique in shadow o the last password changes are not in the future 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. OPTIONS
The options which apply to the pwck command are: -q Report errors only. The warnings which do not require any action from the user won't be displayed. -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. CONFIGURATION
The following configuration variables in /etc/login.defs change the behavior of this tool: PASS_MAX_DAYS (number) The maximum number of days a password may be used. If the password is older than this, a password change will be forced. If not specified, -1 will be assumed (which disables the restriction). PASS_MIN_DAYS (number) The minimum number of days allowed between password changes. Any password changes attempted sooner than this will be rejected. If not specified, -1 will be assumed (which disables the restriction). PASS_WARN_AGE (number) The number of days warning given before a password expires. A zero means warning is given only upon the day of expiration, a negative value means no warning is given. If not specified, no warning will be provided. FILES
/etc/group Group account information. /etc/passwd User account information. /etc/shadow Secure user account information. EXIT VALUES
The pwck command exits with the following values: 0 success 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 6 can't sort password files SEE ALSO
group(5), grpck(8), passwd(5), shadow(5), usermod(8). System Management Commands 06/24/2011 PWCK(8)

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PWCONV(8)						    System Management Commands							 PWCONV(8)

NAME
pwconv, pwunconv, grpconv, grpunconv - convert to and from shadow passwords and groups SYNOPSIS
pwconv pwunconv grpconv grpunconv DESCRIPTION
The pwconv command creates shadow from passwd and an optionally existing shadow. The pwunconv command creates passwd from passwd and shadow and then removes shadow. The grpconv command creates gshadow from group and an optionally existing gshadow. The grpunconv command creates group from group and gshadow and then removes gshadow. These four programs all operate on the normal and shadow password and group files: /etc/passwd, /etc/group, /etc/shadow, and /etc/gshadow. Each program acquires the necessary locks before conversion. pwconv and grpconv are similar. First, entries in the shadowed file which don't exist in the main file are removed. Then, shadowed entries which don't have `x' as the password in the main file are updated. Any missing shadowed entries are added. Finally, passwords in the main file are replaced with `x'. These programs can be used for initial conversion as well to update the shadowed file if the main file is edited by hand. pwconv will use the values of PASS_MIN_DAYS, PASS_MAX_DAYS, and PASS_WARN_AGE from /etc/login.defs when adding new entries to /etc/shadow. Likewise pwunconv and grpunconv are similar. Passwords in the main file are updated from the shadowed file. Entries which exist in the main file but not in the shadowed file are left alone. Finally, the shadowed file is removed. Some password aging information is lost by pwunconv. It will convert what it can. BUGS
Errors in the password or group files (such as invalid or duplicate entries) may cause these programs to loop forever or fail in other strange ways. Please run pwck and grpck to correct any such errors before converting to or from shadow passwords or groups. CONFIGURATION
The following configuration variable in /etc/login.defs changes the behavior of grpconv and grpunconv: MAX_MEMBERS_PER_GROUP (number) Maximum members per group entry. When the maximum is reached, a new group entry (line) is started in /etc/group (with the same name, same password, and same GID). The default value is 0, meaning that there are no limits in the number of members in a group. This feature (split group) permits to limit the length of lines in the group file. This is useful to make sure that lines for NIS groups are not larger than 1024 characters. If you need to enforce such limit, you can use 25. Note: split groups may not be supported by all tools (even in the Shadow toolsuite). You should not use this variable unless you really need it. The following configuration variables in /etc/login.defs change the behavior of pwconv: PASS_MAX_DAYS (number) The maximum number of days a password may be used. If the password is older than this, a password change will be forced. If not specified, -1 will be assumed (which disables the restriction). PASS_MIN_DAYS (number) The minimum number of days allowed between password changes. Any password changes attempted sooner than this will be rejected. If not specified, -1 will be assumed (which disables the restriction). PASS_WARN_AGE (number) The number of days warning given before a password expires. A zero means warning is given only upon the day of expiration, a negative value means no warning is given. If not specified, no warning will be provided. FILES
/etc/login.defs Shadow password suite configuration. SEE ALSO
grpck(8), login.defs(5), pwck(8). System Management Commands 06/24/2011 PWCONV(8)
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