To change a user password on Red Hat Enterprise Linux (RHEL), you can use the passwd command as follows: Log in to the system as the root user or as a user with sudo privileges. Open a terminal window and type the following command to change the password for a specific user: passwd username Replace … Read more

In Linux or Unix, the sed command can be used to remove the ^M character (carriage return) from a file, which is often seen when files are transferred between Windows and Unix systems. Here’s an example sed command that removes the ^M character from a file: sed -i ‘s/\r//’ file.txt In this command, the -i … Read more

To read a file line by line in a Ksh (Korn shell) script on Unix, you can use a while loop with the read command. Here’s an example script that demonstrates how to read a file line by line in Ksh: #!/bin/ksh while read line do echo $line done < file.txt In this script, the … Read more

Views in BIND 9 are used to partition DNS information so that different DNS clients can see different sets of records. This can be useful in scenarios where you have both internal and external DNS clients that need to see different sets of records. To configure views in BIND 9 to partition external and internal … Read more

To configure mod_ssl for Apache on CentOS or RedHat, you can follow these steps: Install mod_ssl: First, you need to install mod_ssl if it is not already installed on your system. You can use the following command to install mod_ssl: yum install mod_ssl Generate SSL certificate and key: To use HTTPS for secure connections, you … Read more

The “Allowed Memory Size” error message in PHP indicates that the script has exhausted the memory limit allocated to it by the PHP configuration. The default memory limit for PHP scripts is 128MB, but this value can be increased or decreased depending on your server configuration. (www.ebsta.com) When you see an error message like “Allowed … Read more

To create a tar archive and keep the files in the local file system, you can use the -C option to change to the directory where the files are located before creating the archive. For example, if you have a directory called myfiles that you want to archive, and you want to create the archive … Read more

Upgrading from FreeBSD 7.2 to FreeBSD 8 can be done using the csup command. Here are the steps to follow: Make sure that you have the latest version of the csup command installed on your system. If not, you can install it using the following command: sudo pkg install csup Backup your configuration files and … Read more

In Linux, Receive Side Scaling (RSS) and Network Adapter Poll Mode (NAPI) are two techniques that can be used to improve the performance of network I/O on multi-core systems. NAPI, in particular, allows for more efficient handling of network traffic by reducing the overhead associated with interrupt handling. To configure NAPI, you can follow these … Read more

In Linux, the noatime option can be used to disable the access time updates on a file system. This can improve the performance of the file system by reducing the number of disk writes required when files are accessed. To disable access time updates on the /var file system, you can follow these steps: Open … Read more