A zombie is already dead, so you cannot kill it. To clean up a zombie, it must be waited on by its parent, so killing the parent should work to eliminate the zombie. An example of how you might send a signal to every process that is the parent of a zombie (note that this […]

Linux default greeters list user names on log in screen. This is sort of a security risk. Using lightdm + slick greeter can avoid this, rendering it back to the key-in username type. To do so, dnf install lightdm slick-greeter systemctl stop gdm (or whatever dm you are using) systemctl disable gdm edit /etc/lightdm/lightdm,conf, change […]

When you are working on a remote server through nomachine or vnc, and there is no video card on the remote server that supports OpenGL > 1.4, the MESA in default render OpenGL version 1.4. This will cause the application to fail even if they do not really need to raise a GUI. Here is […]

Nomachine uses port 4000, however, the server may not have that port opened to your local IP. However, as long as you can ssh the server, you can use the following ssh tunnel to use Nomachine – securely and fast: From a ssh client, do: ssh -L <port>:localhost:4000 -N -f <username>@<nomachine_server> From your nomachine client, […]

Scponly from CentOS 7 cannot chroot. Problem is that /sbin/scponlyc does not have corrent SUID. Do a chmod 4755 /sbin/scponlyc resolves it.

Ganglia web interface cannot display charts in CentOS7, if php is updated to version 7. This is because /usr/share/ganglia/cluster_view.php in line 34, $context_metrics[] was originally initialized as “”, in line 26. If changing line 26 to $context_metrics = []; The problem is fixed.

ssh to a linux box slow after keyed in password, taking 10+ seconds. If using ssh -v, found all the waiting spend on debug info: debug1: pledge: exec This usually happen when something stuck on the systemd-logind service. Restart this service by running systemctl restart systemd-logind usually resolves this without rebooting the box.

This happens when systemd attemps to reload some previously saved state but was not able to. By “kill -1 1” to let it reload itself, systemctl works again without rebooting.

tar cf – folder_name -P | pv -s $(du -sb folder_name | awk ‘{print $1}’) | gzip > folder_zip.tgz

export LIBRARY_PATH=/path