Tag: linux

Why Your Cron Job Is Failing Silently

PATH is different in cron, stdout is muted, and MAILTO breaks silently. Learn cron traps and how to debug them.

SSH Multiplexing: Stop Reconnecting Every Time

Master SSH ControlMaster, ControlPath, and ControlPersist. Reuse connections for lightning-fast SSH, SCP, and rsync operations.

The Linux OOM Killer: Why It's Killing Your App

Why Linux kills your app with no warning. Understand the OOM killer, read dmesg logs, and shield critical processes with oom_score_adj and swap.

find Flags You Keep Forgetting

Practical find command examples: -mtime, -newer, -type, -exec vs xargs, -not, size filters. The patterns you google every time.

The SSH Config File: The Shortcut You're Not Using

Master ~/.ssh/config: Host aliases, HostName, User, Port, IdentityFile, ProxyJump. Stop typing long SSH commands. One-line setup.

Why kill -9 Is the Wrong Default

Signals explained: SIGTERM vs SIGKILL, graceful shutdown, and when to actually use kill -9.

The umask You've Been Ignoring

Understand Linux umask: what it is, how 022 and 027 work, calculating file permissions, and why it matters for shared directories and security.

/proc as a Debugging Tool

The /proc filesystem is a live window into every running process on Linux. Debug PIDs, file descriptors, memory, and limits with no extra tools installed.

zram vs Swap: What's Actually Faster for Low-RAM Servers

Compare zram (compressed RAM) and traditional swap files. Learn when each works, setup, and real-world performance trade-offs for memory-constrained systems.

strace for Beginners: See What Any Process Is Doing

Use strace to trace system calls and debug mysterious permission errors, missing files, and network issues without ever reading source code.

Using the Clipboard from the Linux Terminal

Copy and paste from the Linux terminal without a mouse. Master xclip, xsel, wl-copy, and integrate clipboard with tmux and SSH.

lsof: The Tool That Shows You Everything

Master lsof to find port conflicts, trace deleted files eating disk, and debug network connections.