Find Lines in One File Not Found in Another File
Explains how to get the lines found in one file that is not present in another file.
Linux: Get Public SSH Key From Private Key
Explains how to retrieve or generate a SSH public key from a private SSH key in OpenSSH format
Linux: Switch to nologin User
Explains how to switch and execute commands or scripts as a user with the nologin shell on Linux.
Linux: Check Inode Usage
Explains how to get the inode usage count and the number of free inodes on a Linux system. Also covers how to find inode number of a file and search for a file using a inode number.
Linux: Use Cat Command to Write to File
Explains how to use here document and the cat command to write to a file on Linux or Unix.
Linux: Add Comment to IPTables Rule
Explains how to view or add comments to iptables rules on Linux.
Bash: Multi-dimensional Arrays
Learn how to simulate a multi-dimensional array in bash using an associate array with clever use of the hash key. Bash 4 only provides one-dimensional indexed and associative array variables.
Linux: Restrict Unprivileged Users From Using dmesg
Explains how to prevent unprivileged users from using dmesg to view messages from the kernel’s log buffer.
Linux: Restrict su to Group
Explains how to restrict the use of su command to a limited number of users belonging to a group.
Linux: Get Number of Days since 1970
Calculate or get the number of calendar days since 1970 on Linux using the date command.
