Packet Filter aka PF is OpenBSD’s system for filtering TCP/IP traffic / NAT software. I always like the simplicity offered by PF firewall. There is a new article that explains the PF performance monitoring: The PF (packet filter) firewall package was introduced in OpenBSD 3.0, and has since been ported to the FreeBSD and NetBSD […]

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You can use the watch command to execute a program or shell script periodically, display its output on screen repeatedly. This allows you to watch the program output change over time. By default, the program is run every 2 seconds. This is useful to monitor memory utilization or disk space usage over time without having to look at scrolling output.


If you need to send an email with a text file (or binary file) as attachment using shell script or command prompt in Unix or Linux; try mutt – a terminal-based e-mail client for Unix-like systems.