To see the CPU temperature on CentOS 7 / Red Hat Enterprise Linux 7, you can use the “lm_sensors” package. This package provides tools to monitor the temperature of various system components, including the CPU. To install the “lm_sensors” package, run the following command: # yum install lm_sensors Once the package is installed, you can … Read more

To see information about PCI devices on CentOS 7 / Red Hat Enterprise Linux 7.x / 8.x, you can use the “lspci” command. The “lspci” command is a part of the “pciutils” package and can be installed by running the following command: # yum install pciutils Once the package is installed, you can run the … Read more

To configure a static IP address on CentOS 7 / RHEL 7, follow these steps: Open the network configuration file: Open the file “/etc/sysconfig/network-scripts/ifcfg-eth0” using a text editor. The “eth0” in the file name refers to the name of the network interface you want to configure. If you have multiple network interfaces, you will have … Read more

You can use the “dd” command to create a disk image on Linux or Unix systems. Here are the steps to create a disk image: Identify the source disk: You can use the “lsblk” or “fdisk -l” command to identify the source disk and partition you want to create the image of. For example, if … Read more

To configure a Wi-Fi and LAN bridged access point in pfSense firewall router, you need to perform the following steps: Connect to the pfSense web interface. Go to Interfaces > (assign) > Bridges and add a new bridge. Give the bridge a descriptive name, such as “WiFiLANBridge”. Select the Wi-Fi and LAN interfaces you want … Read more

To create a “cron.log” file to log crontab logs on Ubuntu 16.04, 18.04, and 20.04, you can use the following steps: Create the “cron.log” file: # touch /var/log/cron.log Change the ownership of the file to the syslog user: # chown syslog:adm /var/log/cron.log Edit the syslog configuration file: # nano /etc/rsyslog.d/50-default.conf Add the following line to … Read more

The “bad username” error message when reading the “/etc/cron.d” file on Linux typically occurs when the username specified in the cron job does not exist on the system. To resolve this issue, you can either: Correct the username in the cron job file: # nano /etc/cron.d/your_cron_job_file Use a valid username that exists on your system. … Read more

To configure Postfix to use an external SMTP server as a relayhost (smarthost), you can use the following steps: Edit the Postfix configuration file: # nano /etc/postfix/main.cf Add or modify the following line: relayhost = smtp.example.com:587 Replace smtp.example.com with the hostname or IP address of your SMTP server and 587 with the port number if … Read more

To install KVM on a headless Ubuntu 16.04 LTS server, you can use the following steps: Verify that your system supports virtualization: # egrep -c ‘(vmx|svm)’ /proc/cpuinfo If the output is 0, your system does not support virtualization. Install the necessary packages: # apt-get update # apt-get install qemu-kvm libvirt-bin bridge-utils Add your user to … Read more

To force users to use secure passwords on Ubuntu or Debian Linux, you can use the “pam_cracklib.so” module in PAM (Pluggable Authentication Modules). This module checks the strength of passwords before allowing them to be set. Here are the steps to enable password checks with PAM: Install the “libpam-cracklib” package: # apt-get install libpam-cracklib Edit … Read more