macOS
303 entries match these filters
- 0343 Fix: Connection refused and Connection timed out, what each one means Refused means the host answered and nothing is listening there. Timed out means no answer at all, usually a firewall or wrong… Beginner · Fixes an error · Linux, macOS Article DNS, IP addresses & ports · Firewalls 15 Oct 2026
- 0325 Fix: SSL certificate problem: unable to get local issuer certificate curl, git, pip or npm cannot chain the server's certificate to a root they trust. Usual causes: a corporate proxy that re-signs… Intermediate · Fixes an error · Linux, macOS, Windows Article Common errors · Making requests · TLS & certificates 15 Oct 2026
- 0326 Fix: too many open files A process hit its file descriptor limit, usually 1024. Raise it for the shell, the systemd unit or the user, fix a… Intermediate · Fixes an error · Linux, macOS Article Performance & tuning · Processes & ports · Services & systemd 15 Oct 2026
- 0327 Docker images, containers and volumes explained An image is a read-only template, a container is a running copy of it with a thin writable layer, and a volume… Beginner · Explains an idea · Linux, macOS, Windows Article Docker basics 15 Oct 2026
- 0303 What is CORS? CORS is a browser rule that decides whether a web page from one site is allowed to call an API on another… Beginner · Explains an idea · Any system Article Making requests 15 Oct 2026
- 0304 What is a cookie? A cookie is a small piece of text a website stores in your browser so it can recognise you on the next… Beginner · Explains an idea · Any system Article Authentication 15 Oct 2026
- 0289 What is a process? A process is a running program; the operating system gives each one its own memory and an ID number. Beginner · Explains an idea · Any system Article Processes & ports 15 Oct 2026
- 0305 What is a token? A token is a string that proves who you are or what you may do, sent with requests instead of a password. Beginner · Explains an idea · Any system Article Authentication 15 Oct 2026
- 0290 What is a cron job? A cron job is a command scheduled to run automatically at set times, such as every night at two o'clock. Beginner · Explains an idea · Any system Article cron & timers 15 Oct 2026
- 0306 What is hashing? Hashing turns any data into a fixed length fingerprint that cannot be reversed, used to check files and store passwords. Beginner · Explains an idea · Any system Article Secrets & access 15 Oct 2026