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.
Linux: Script to Partition Disk
Learn how to automate the partitioning of a disk using fdisk, parted and sfdisk on Linux.
Linux: Check User Password Expiry Time
Explains how to check user account password expiry information on Linux.
Unix / Linux: Manage Multiple SSH Keys
Manage multiple ssh private keys and configure ssh to map different private keys to different hosts automatically by using ~/.ssh/config configuration file
Linux: TOTP Password Generator
Explains how to generate TOTP one-time passwords on Linux using oathtool.
