Learning Modern Linux

Appendix A. Helpful Recipes

In this appendix, I’ve compiled a list of recipes for common tasks. This is just a selection of recipes that I’ve gathered over time, tasks that I often carry out and like to have handy as a reference. By no means is this a complete or deep coverage of Linux usage and admin tasks. For a comprehensive collection of recipes, I strongly recommend you check out Carla Schroder’s Linux Cookbook (O’Reilly), covering a range of recipes in great detail.

Gathering System Information

To learn about the Linux version, kernel, and other related information, use any of the following commands:

cat /etc/*-release
cat /proc/version
uname -a

To learn about basic hardware equipment (CPU, RAM, disks), do:

cat /proc/cpuinfo
cat /proc/meminfo
cat /proc/diskstats

To learn more about the hardware of your system, such as about the BIOS, use:

sudo dmidecode -t bios

Note for the previous command: other interesting options for -t include system and memory.

To query overall main memory and swap usage, do:

free -ht

To query how many file descriptors a process can have, use:

ulimit -n

Working with Users and Processes

You can list logged-in users with either who or w (more detailed output).

To show system metrics (CPU, memory, etc.) on a per-process basis for a specific user, SOMEUSER, use the following command:

top -U SOMEUSER

List all processes (for all users) in tree format with details by using:

ps faux

Find a specific process (python here):

ps -e | grep python

To terminate ...