Focused, hands-on DevOps and server-side problems with hints, feedback, and automated solution checks.
A Go service that has always been shipped as a static binary in a scratch-y image suddenly fails to start in a container, while the local build works as before. Find what recent changes caused it and fix the image without reverting them.
A stubborn process is running on the system, kill it :)
Refactor a slow, single-threaded C file downloader that fetches files sequentially into a multi-threaded program using POSIX Threads (pthreads) to achieve concurrent downloads.
Write a C program that calls fork() to clone a process and execve() to execute a command, then print and retrieve the child process PID.
Compile a small C loop with -O2 -S, inspect the generated assembly, report how many add instructions gcc produced and see how much it has optimized the equasion.
Run gcc -E on a small C program and find the exact line where the preprocessor expanded a macro into a printf call.
Produce a valid ELF binary that runs and exits cleanly, but does not define a main() function.
Make a single echo server listen on either a TCP socket or a Unix domain socket, selected by its command-line argument. The challenge illustrates that the same stream-socket workflow works with two address families (AF_INET and AF_UNIX).
Write a TCP client to hold a back-and-forth conversation with a "chat" server: send a line, read the reply, send another line - repeat until the session is over. A hands-on lesson in designing an application protocol on top of a byte-oriented TCP stream.
Write your first TCP client for a push-only telemetry server that starts sending sensor readings as soon as you connect. Likely the easiest way to get started with TCP socket programming.
