SUBGID(5) File Formats and Conversions SUBGID(5)
NAME
subgid - the subordinate gid file
DESCRIPTION
Each line in /etc/subgid contains a user name and a range of subordinate group ids that user is allowed to use. This is specified with
three fields delimited by colons (":"). These fields are:
o login name or UID
o numerical subordinate group ID
o numerical subordinate group ID count
This file specifies the group IDs that ordinary users can use, with the newgidmap command, to configure gid 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/subgid, 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
/etc/subgid
Per user subordinate group IDs.
/etc/subgid-
Backup file for /etc/subgid.
SEE ALSO
login.defs(5), newgidmap(1), newuidmap(1), newusers(8), subuid(5), useradd(8), userdel(8), usermod(8), user_namespaces(7).
shadow-utils 4.5 01/25/2018 SUBGID(5)
