66 cards
This deck walks you through Linux file permissions from the ground up, starting with the meaning of symbolic patterns like rwxr-xr-- and moving into the numeric equivalents such as 644, 755, 600, and 700. As you progress, you'll practice translating between the two notations, explore special bits like setuid, setgid, and the sticky bit, and learn why permissions matter in real situations such as securing an ~/.ssh directory. You'll also cover recursive changes, ownership commands, reading permissions with ls, and how umask shapes the defaults for newly created files and folders.
It's a great fit if you're a beginner learning the Linux command line, a sysadmin refreshing the fundamentals, or a developer who has been getting away with copy-pasted chmod commands and now wants to understand what's actually happening. The mix of symbolic and numeric formats means you'll build fluency in both, which is essential for reading scripts, troubleshooting permission errors, and passing common certification topics.
To get the most out of these cards, try to visualize a file's mode bits as three independent sets (owner, group, other) rather than memorizing patterns as single numbers. When studying, pause to actually open a terminal and run ls -l, chmod, and umask on a scratch directory so the conversions move from abstract rules to muscle memory. Spacing your review over several short sessions tends to work better than cramming, especially since the special bits (setuid, setgid, sticky) benefit from repeated exposure before they fully stick.