PWCONV linux command manual
pwconv, pwunconv, grpconv, grpunconv - convert to and from shadow
passwords and groups.
These four programs all operate on the normal and shadow password and
group files: /etc/passwd, /etc/group, /etc/shadow, and /etc/gshadow.
pwconv creates shadow from passwd and an optionally existing shadow.
pwunconv creates passwd from passwd and shadow and then removes
shadow. grpconv creates gshadow from group and an optionally existing
gshadow. grpunconv creates group from group and gshadow and then
Each program acquires the necessary locks before conversion.
pwconv and grpconv are similiar. 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
Likewise, pwunconv and grpunconv are similiar. 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.
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.
login.defs(5), grpck(8), pwck(8)
26 Sep 1997 PWCONV(8)