You can check the version of the Linux kernel that’s currently running on your Ubuntu system using the following command: uname -r The uname command provides information about the system and its environment, and the -r option specifically requests the release information, which is the version of the Linux kernel. You can also use the … Read more
Here are some common examples of the host command in Linux and Unix: To perform a simple DNS lookup for a hostname, you can run the following command: host example.com To perform a reverse DNS lookup for an IP address, you can run the following command: host 8.8.8.8 You can also specify the DNS server … Read more
The dig command in Linux and Unix is used to query the Domain Name System (DNS) to retrieve information about hostnames, IP addresses, and other DNS-related information. The dig command can be used to perform various types of DNS lookups, such as checking the A (address) record for a hostname, the MX (mail exchange) record … Read more
There are several ways to find memory usage information on a CentOS Linux system. Here are some common commands: free: This command displays the amount of free and used memory in the system, as well as the swap space usage. The output is in kilobytes: $ free -h The -h option displays the output in … Read more
The ip command is a versatile tool for managing and querying network interfaces and IP addresses on a Linux system. Here are some common examples of using the ip command: Display information about all network interfaces: $ ip addr show Display information about a specific network interface: $ ip addr show eth0 Replace eth0 with … Read more
You can restart the Iptables firewall on a CentOS Linux server by executing the following steps: Stop the Iptables firewall service: $ sudo service iptables stop Flush all current Iptables rules: $ sudo iptables -F Start the Iptables firewall service: $ sudo service iptables start Alternatively, you can restart the Iptables firewall service by executing … Read more
You can reload the Squid proxy server configuration without restarting the Squid daemon by sending a SIGHUP signal to the Squid process. This will cause Squid to reread its configuration file, squid.conf, and apply any changes. Here’s how to reload the Squid proxy server on a Linux system: Find the process ID (PID) of the … Read more
The sed command is a powerful tool in Linux and Unix for text processing and manipulation. You can use the sed command to substitute multiple patterns, or to find and replace text within a file. Here’s how you can use sed to substitute multiple patterns in a file: Substitute multiple patterns in place To substitute … Read more
You can check the version of PHP installed on a Linux or Unix server by using the following methods: From the command line: You can run the following command in your terminal or shell to display the version of PHP installed on the server: $ php -v PHP 7.3.22-1+ubuntu18.04.1+deb.sury.org+1 (cli) Copyright (c) 1997-2021 The PHP … Read more
The id command in Unix-like systems is used to display the user and group information for the current user or a specified user. It can display information such as the user ID (UID), group ID (GID), and the groups that the user belongs to. Here are some examples of how to use the id command: … Read more