In Linux/UNIX, you can use the date command to convert epoch seconds to the current time. Here’s an example: #!/bin/bash # Set epoch seconds to a variable epoch_seconds=”1632718301″ # Use the date command to convert epoch seconds to human-readable time formatted_time=$(date -d @$epoch_seconds) echo “Epoch seconds: $epoch_seconds” echo “Formatted time: $formatted_time” In this example, we … Read more
To find out if a variable contains a substring in Bash, you can use the [[ operator along with the == operator or the =~ operator. Here is an example using the == operator: #!/bin/bash string=”Hello World” if [[ “$string” == *ello* ]]; then echo “Substring found” else echo “Substring not found” fi In this … Read more
No, you do not have to recompile all installed applications after recompiling the Linux kernel. When you recompile the Linux kernel, you are essentially creating a new kernel image file that contains the new kernel code and configuration options. This new kernel image file is then used when the system boots up. Most user-level applications … Read more
To verify if NTP (Network Time Protocol) is working or not and check the status of NTP, you can use the following commands: Check if the NTP daemon is running: sudo systemctl status ntp This will show you the status of the NTP daemon and whether it is running or not. If it is not … Read more
To encrypt a backup tape using tar and OpenSSL in Linux/UNIX, you can follow these steps: Create a backup archive using tar command. For example, to create a backup of /home directory, run: tar czvf /dev/st0 /home This will create a compressed backup of the /home directory and write it to /dev/st0 tape device. Use … Read more
In Bash, you can use parameter expansion to trim leading white space from input variables. Here’s an example: #!/bin/bash input=” hello world” trimmed=${input#”${input%%[![:space:]]*}”} echo “Original input: \”$input\”” echo “Trimmed input: \”$trimmed\”” In this example, the input variable is assigned a value with leading white space. The trimmed variable uses parameter expansion to remove the leading … Read more
In Lighttpd, you can use the mod_setenv module to send custom headers to the client. Here’s how you can do it: Enable the mod_setenv module: If the mod_setenv module is not already enabled, you’ll need to enable it in your Lighttpd configuration file. Add the following line to the file: server.modules += (“mod_setenv”) Set the … Read more
Upgrading Red Hat Enterprise Linux (RHEL) to version 5.5 involves a few steps. Here is a general procedure to upgrade RHEL to version 5.5: Backup your system: Before you upgrade your system, make sure you have a backup of your system in case anything goes wrong. Update your current version: Make sure that your current … Read more
When you’re editing a file in Vim/Vi and you need to save the changes to the file, but you don’t have the necessary permissions, you can use the :w !sudo tee % command to save the file with root permission. Here are the steps: Open the file with Vim/Vi: Open the file you want to … Read more
To set up a reverse proxy with SSL (Secure Sockets Layer) on Nginx, you’ll need to follow these steps: Install and configure Nginx: First, you’ll need to install Nginx on your server and configure it as a reverse proxy. You can follow the official Nginx installation guide for your Linux distribution to install Nginx. Generate … Read more