DevOps is a set of practices, tools, and a cultural philosophy that automate and integrate the processes between software development and IT teams. It emphasizes team empowerment, cross-team communication and collaboration, and technology automation.
The automatic documentation, type hints, and async support make development so much faster. Plus, the performance is incredible!
I've been struggling with async programming for months, but FastAPI's approach finally made it click. Using 'async def' for endpoints and 'await' for database calls just makes sense.
The folder structure in Linux follows the FHS (Filesystem Hierarchy Standard). FHS: /bin - base command binaries /boot - bootloader files /dev - devices /etc - PC configuration /home - home folders /lib - libraries and kernel modules /proc - information about the running system /media - mounting media (/mnt) /opt - additional software /root - admin home folder /sbin - main system configuration programs (firewall, iptables) /srv - data for system services /tmp - temporary files /usr - user binaries /var - variable files (frequently changing)
The way Pydantic handles validation in FastAPI is incredible. Define your model with type hints, and boom - automatic validation, serialization, and documentation. No more writing validation code by hand!
System startup: firmware stage (BIOS/UEFI, bootloader search) -> bootloader stage (GRUB, OS kernel selection menu, OS unloading and temporary file system in RAM) -> kernel stage (Kernel, hardware initialization, temporary file system initialization) -> system initialization stage (systemd/PID1, service startup, reaching systemd target state) -> user space (login manager starts).
nproc - find out the number of cores ulimit - find and change shell resources (-n number of open files) apt list --installed | grep ssh - search installed packages apt search == apt-cache search some_package - search for a package by name and description apt-cache pkgnames curl - search for a package by name apt show curl - search from a local updated list ps -ef - displays a full list of all processes running on the system in standard (full-format) format htop - display information (like top) systemctl show - displays the parameters and status of the systemd system manager itself systemctl show nginx - displays a full list of the internal properties and settings of the nginx service pidof name - display the PID of the command/program name iptables (-L) - a standard tool for viewing, creating, and configuring a firewall. netstat - Shows detailed information about the computer's network activity (list of all connections, open (listening) ports, program names and their PIDs, connection status, network statistics, routing table (similar to route -n), multicast group membership, queue status). 0.0.0.0:22 - means listening on port 22 route -n - Displays the kernel routing table lsof -p <PID> - Shows all open objects accessed by a specific process lsof -i :80 - Find the process listening on a specific port (e.g., 80) lsof -u user1 :w !sudo tee % - Write data if vim was opened without sudo hostname - Displays the hostname (the computer's network name; it can also be accessed using a loopback or its own IP address)..
You can telnet google.com 80 to use Telnet as a simple web client (besides remote access). On windows cmd you can press Ctrl + ] to open telnet configuration: set localecho - to see what was typed. Each keystroke is a separate TCP packet, which is immediately sent to the server.
FastAPI's dependency injection system is so elegant. Need a database session? Just add it as a parameter. Need the current user? Same thing. It makes the code so clean and testable.
L1 - Data Link Layer: physical and data link layers from OSI; L2 - Internetwork Layer: network layer from OSI; L3 - Transport Layer: transport layer from OSI; L4 - Application Layer: session, presentation, application layers from OSI.