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.
Kernel, CPU, memory and uptime: the first commands on a box you've never seen.
unameShow the kernel name, version and architectureBeginnerhostnameShow or set the system's host nameBeginnerlscpuShow CPU architecture, cores, threads and cachesBeginnerfreeShow used, free and available memoryBeginneruptimeHow long the system has run, and its load averageBeginnervmstatReport CPU, memory, swap and I/O activity over timeIntermediateiostatMeasure disk throughput, latency and utilisationIntermediate