Dear Experts,
Could someone enlighten me about the following file:
/etc/subuid
? This file appears to be owned by "setup" package. This is CentOS 7
system, and until now these files if existed were never changed. Today I
have added user quite routine way, by doing
/usr/sbin/groupadd -g 4500 [username]
/usr/sbin/useradd -g [username] -u 4500 -c "User Name, email@domain"
[username]
And the file /etc/subuid changed and user was added into it:
[username]:100000:65536
Nothing like that was happening before. This is first time I create
account after update done on Oct 3, 2019. I checked several CentOS 7
machines, basically doing this:
# grep subuid /usr/sbin/useradd
Binary file /usr/sbin/useradd matches
And CentOS 7 machines indeed may have that file name in the useradd
binary. None of CentOS 6 machines has that.
I tried to do FreeBSD-ism:
man /etc/subuid
came empty, and realized that I'm doing FreeBSD-ism.
I tried to do search on the web (did not "google", I use duckduckgo...
so I "did search"), and came pretty much empty.
Is it just me, or indeed something in CentOS 7 indeed changed? And what
is it?
Another question on the same note: how do we find out what the file is
about and is used for in Linux, apart from searching on the web. (When
there are surprises like the one I had today, one does like to know what
this particular file is used for).
Thanks in advance for your answers.
Valeri
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Valeri Galtsev
Sr System Administrator
Department of Astronomy and Astrophysics
Kavli Institute for Cosmological Physics
University of Chicago
Phone: 773-702-4247
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