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pwck - Unix, Linux Command
NAME
pwck - verify integrity of password files
SYNOPSIS
Tag | Description |
pwck [-q] [-s] [passwd shadow]
pwck [-q] [-r] [passwd shadow]
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DESCRIPTION
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:
Tag | Description |
o
|
the correct number of fields
|
o
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a unique user name
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o
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a valid user and group identifier
|
o
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a valid primary group
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o
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a valid home directory
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o
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a valid login shell
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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:
Tag | Description |
-q
|
Report errors only. The warnings which do not require any action from the user wont be displayed.
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-r
|
Execute the
pwck
command in read-only mode.
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-s
|
Sort entries in
/etc/passwd
and
/etc/shadow
by UID.
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By default,
pwck
operates on the files
/etc/passwd
and
/etc/shadow. The user may select alternate files with the
passwd
and
shadow
parameters.
FILES
Tag | Description |
/etc/group
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Group account information.
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/etc/passwd
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User account information.
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/etc/shadow
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Secure user account information.
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SEE ALSO
group(5),
passwd(5),
shadow(5),
usermod(8).
EXIT VALUES
The
pwck
command exits with the following values:
Tag | Description |
0
|
success
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1
|
invalid command syntax
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2
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one or more bad password entries
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3
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cant open password files
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4
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cant lock password files
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5
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cant update password files
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