Category: Computer Tips

If only to replace a system drive, doing a dd of old drive to new drive will work. However, in most of cases the driving force of replacing drives is that the drive size is not big enough to host increasing size of system files. In this case, only doing dd will screw you up […]

If you are using tcsh shell, and your login script has screen output like an echo line, scp will be interrupted. To prevent this, knowing that for an interactive ssh session, it will open a tty, but embedded session like scp will not generate a tty. Thus this can be distinguished by checking if the […]

rsync -ax ssh -t user@host –noprofile

E-Prime 3 got a new issue with recent Windows 10 update. The presentation nearly always stuck at the end of the first item. Diagnose showed that only when E-Prime/E-Run was running on CPU 0, it can finish properly. To enforce this, a shortcut is created for each E-Run file with the target as C:\Windows\System32\cmd.exe /c […]

My Mellanox MSN2100 switch constantly has the “system status” LED on red since purchase. By looking into its system status: show system-health detail System status summary System status LED redServices:Status: OKHardware:Status: Not OKReasons: Failed to get speed tolerance for fan4Failed to get speed tolerance for fan3Failed to get speed tolerance for fan2Failed to get speed […]

The Mellanox/NVidia MSN2100 switch came with a bare ONIE system and is not Plug and Play. NVidia service can not provide setting up assistance without a ONYX//Cumulus/SONiC entitlement. I installed the community version of SONiC from sonic.software for sonic-mellanox.bin. After the installation, the switch is automatically configured with all 16 ports as routers with a […]

Sometimes your NFS mount stopped response. You cannot umount normally, if you use umount -l to unmount it, you cannot mount it again, Mounting attempt stalls too. The suggestion on the interenet was to just reboot the client. But you may have important jobs or services on it and you really do not want to. […]

Sometimes when an dnf update was unexpectedly terminated like a power failure, the system may leave an inconsistent rpm database. If this happens, in most case by rebuilding rpm database (rpmdb –rebuilddb), and to use (package-cleanup –cleandupes), it could be fixed. For some severe case, after both, when you are trying to run (dnf update […]

If ForwadX11 and ForwardX11Trusted are both enabled in /etc/ssh/ssh_config, when you do “ssh host” it will invoke X11 forwarding by default. This is convenient when you frequently need to run programs with GUI on remote host. However, with X11 forwarding, if you are simply running a text mode command/script via ssh, like “ssh node ls” […]

echo <your password> | ssh <node name> “sudo -S <command>”