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Unix
The system around the shell.
- •150 XPPATH & EnvironmentHow the shell finds commands.
- •150 XPProcesses & SignalsWhat runs, how it's controlled, and how to stop it.
- •150 XPPermissions & OwnershipWho can read, write, or execute — and why it matters.
- •150 XPFilesystem & LinksInodes, hard links, symlinks, and where config lives.
- •200 XPPipes, I/O & jqstdin, stdout, stderr — and the essential JSON knife.