SUBUID(5)               File Formats and Conversions               SUBUID(5)

NAME         top

       subuid - the subordinate uid file

DESCRIPTION         top

       Each line in /etc/subuid contains a user name and a range of
       subordinate user ids that user is allowed to use. This is specified
       with three fields delimited by colons (“:”). These fields are:

       ·   login name or UID

       ·   numerical subordinate user ID

       ·   numerical subordinate user ID count

       This file specifies the user IDs that ordinary users can use, with
       the newuidmap command, to configure uid mapping in a user namespace.

       Multiple ranges may be specified per user.

       When large number of entries (10000-100000 or more) are defined in
       /etc/subuid, parsing performance penalty will become noticeable. In
       this case it is recommended to use UIDs instead of login names.
       Benchmarks have shown speed-ups up to 20x.

FILES         top

       /etc/subuid
           Per user subordinate user IDs.

       /etc/subuid-
           Backup file for /etc/subuid.

SEE ALSO         top

       login.defs(5), newgidmap(1), newuidmap(1), newusers(1), subgid(5),
       useradd(8), userdel(8), usermod(8), user_namespaces(7).

COLOPHON         top

       This page is part of the shadow-utils (utilities for managing
       accounts and shadow password files) project.  Information about the
       project can be found at ⟨http://pkg-shadow.alioth.debian.org/⟩.  If
       you have a bug report for this manual page, see
       ⟨http://pkg-shadow.alioth.debian.org/getinvolved.php⟩.  This page was
       obtained from the project's upstream Git repository
       ⟨git://anonscm.debian.org/git/pkg-shadow/shadow.git⟩ on 2018-02-02.
       (At that time, the date of the most recent commit that was found in
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       lems in this HTML version of the page, or you believe there is a bet‐
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       or improvements to the information in this COLOPHON (which is not
       part of the original manual page), send a mail to man-pages@man7.org

shadow-utils 4.4                 02/02/2018                        SUBUID(5)

Pages that refer to this page: newuidmap(1),  subgid(5),  user_namespaces(7),  newusers(8),  useradd(8),  userdel(8),  usermod(8)

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