SJSeung Joo Ahninfrogsdevlog.hashnode.dev·May 12 · 5 min read[Day 11] cron & Bash Scripting — Automating Tasks in LinuxDay 10 covered journalctl for analyzing logs. But repetitive tasks like "clean up old logs every day at 3 AM" shouldn't be done manually. That's what cron is for. 1. cron = An OS-Level Scheduler If y00
SJSeung Joo Ahninfrogsdevlog.hashnode.dev·May 7 · 5 min read[Day 10] journalctl — Finding Problems Through LogsDay 9 covered systemd managing services. Unit files, service registration, auto-restart on failure. But when something breaks on a server running 50 services, you can't run systemctl status on each on00
SJSeung Joo Ahninfrogsdevlog.hashnode.dev·May 7 · 6 min read[Day 9] systemd — Who Wakes Up All These Processes?Day 8 was about pipelines. Chaining grep, awk, sort, and uniq -c together to aggregate socket states. Each tool is simple on its own, but piped together they become powerful. Today I took a step back.00
SJSeung Joo Ahninfrogsdevlog.hashnode.dev·Apr 23 · 8 min read[Day 8] Linux Pipes Are Just Plumbing — And I Already Had the WrenchesDay 7 ended with a real shift in how I think about sockets. The kernel owns them. Processes just hold pickup tickets. accept() isn't accepting — it's picking up what the kernel already prepared. Today00
SJSeung Joo Ahninfrogsdevlog.hashnode.dev·Apr 22 · 12 min read[Day 7] The Process Went to Sleep — and the Kernel Kept WorkingIn Day 6, I watched a single connection arrive at the server and saw two fds show up instead of one. The listening socket (fd 3) stayed at the door, and a new connected socket (fd 4) was created for t00
