Watch each command run in a real-looking terminal, see what every part of it means, then try it yourself with practice tasks. From ls to kubectl.
The first three commands on any server: where am I, what's here, and how full is the disk.
Write reliable bash: variables, tests, loops, functions, exit codes and traps.
bash: variablesShell variables: assign, quote, default and exportBeginnerbash: ifConditions: if, elif, else, test brackets and caseBeginnerbash: loopsLoops: for, while read, until and retryBeginnerbash: functionsFunctions: name a block, pass arguments, return a statusIntermediatebash: arraysArrays: lists and key-value maps in bashIntermediatebash: exit codesExit codes, $?, set -euo pipefail and trapIntermediatebash: redirectionRedirection: stdout, stderr, 2>&1, /dev/null and here-docsBeginnerbash: argumentsScript arguments: $1, $#, "$@", shift and getoptsIntermediate