On 2019-10-09 15:47, Valeri Galtsev wrote: > 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 at 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. A quick google search: https://lmgtfy.com/?qtype=search&q=%2Fetc%2Fsubuid yielded this as the first link: http://man7.org/linux/man-pages/man5/subuid.5.html -- Mike Burger http://www.bubbanfriends.org "It's always suicide-mission this, save-the-planet that. No one ever just stops by to say 'hi' anymore." --Colonel Jack O'Neill, SG1