You can use the remote source command with the ssh command to set a variable locally from a remote server. Here’s an example in bash: VAR=$(ssh user@remote-server “source ~/.bashrc; echo \$VAR”) In this example, the ssh command connects to the remote server as user, sources the ~/.bashrc file, and then echoes the value of the … Read more
You can set the http_proxy environment variable with a password that contains special characters by URL encoding the password. The URL encoding replaces special characters with their hexadecimal representation. Here’s an example of setting the http_proxy variable with a password that contains special characters: export http_proxy=”http://username:$(echo -n “pass#word” | xxd -plain | tr -d ‘\n’ … Read more
To limit the network bandwidth of a specific user’s shell account in Linux, you can use the trickle command. Trickle is a user-space bandwidth shaper that can be used to limit the network bandwidth of individual programs. Here is how to limit the network bandwidth of a specific user’s shell account: Install trickle: sudo apt-get … Read more
To bind a MySQL/MariaDB server to multiple IP addresses, you can follow these steps: Open the MySQL/MariaDB configuration file: sudo nano /etc/mysql/my.cnf Locate the bind-address directive and comment it out or delete it: # bind-address = 127.0.0.1 Add the following lines to the configuration file to specify the IP addresses that the server should listen … Read more
To install the latest version of OpenShot on Debian or Ubuntu, follow these steps: Add the OpenShot PPA (personal package archive) to your system: sudo add-apt-repository ppa:openshot.developers/ppa Update the package list: sudo apt-get update Install OpenShot: sudo apt-get install openshot-qt After the installation is complete, you can launch OpenShot from the application menu or by … Read more
SELinux (Security-Enhanced Linux) is a Linux kernel security module that provides a mechanism for enforcing mandatory access control (MAC) policies. MAC is a type of access control that restricts the actions that can be performed by processes and users on a system. SELinux was developed by the United States National Security Agency (NSA) and was … Read more
To gracefully restart an Nginx web server after making changes to a configuration file, you can use the following command: nginx -s reload This command sends a SIGHUP signal to the Nginx master process, which causes the master process to reload its configuration file and pass the new configuration to its worker processes. The -s … Read more
In bash shell, you can check if a variable is empty or not using the following syntax: if [ -z “$VARIABLE_NAME” ]; then echo “Variable is empty” else echo “Variable is not empty” fi The -z operator checks if the length of the string stored in the $VARIABLE_NAME is zero, indicating that the variable is … Read more
In OpenBSD, FreeBSD, and NetBSD, you can list the rules in a PF firewall using the following command: pfctl -sr This command will display a list of the rules in the firewall, including both the filter and the nat rules. The output of this command provides information about the direction of the rule (in/out), the … Read more
In CentOS/RHEL version 5 and 6, you can update your system using the following command: yum update This command will update all installed packages to the latest version available in the configured repositories. You can run this command regularly to keep your system up-to-date with the latest security patches and bug fixes. Note: Before you … Read more