Thank you very much for your valuable comments.
Also, There is a centos 7.6 server in the system, how can I update it to 7.8 or 7.9. if I just run yum update. is there any obstacle for this and is the method correct ?
Sudo versions
Re: Sudo versions
yum update will take you to the latest version of everything (within CentOS 7, i.e. it will not "upgrade" you to 8).
The future appears to be RHEL or Debian. I think I'm going Debian.
Info for USB installs on http://wiki.centos.org/HowTos/InstallFromUSBkey
CentOS 5 and 6 are deadest, do not use them.
Use the FAQ Luke
Info for USB installs on http://wiki.centos.org/HowTos/InstallFromUSBkey
CentOS 5 and 6 are deadest, do not use them.
Use the FAQ Luke