Tag: linux

curl Flags Every Developer Should Know

Master the curl flags that'll save you hours debugging APIs, downloads, and web requests. From -X to --compressed, here's what actually matters.

Named Pipes (FIFOs) in Shell Scripts

Named pipes (FIFOs) let you buffer and synchronize between processes. They're underused but solve real problems: queuing, coordination, and complex data flows.

UFW Advanced: Rate Limiting, Logging, and Rules That Actually Make Sense

Go beyond ufw allow/deny: rate limiting with ufw limit, logging levels, before.rules for iptables, IPv6 handling, Docker bypass fixes, and fail2ban integration.

Bash Arrays: The Feature That Makes Scripts Readable

Declare, iterate, slice, and manipulate bash arrays safely. Indexed and associative arrays, the @ vs * trap, and patterns that make scripts readable.

Bash Process Substitution: What <() and >() Actually Do

Process substitution lets you treat a command's output as a file, and feed input to a command as if it were a file. It's weird but powerful.

Here Documents vs Here Strings in Bash

Bash heredocs and here strings explained: <<EOF for multiline input, <<-EOF for tab-indented blocks, <<<string for single lines, and when to use each.

GNU parallel for Embarrassingly Parallel Tasks

GNU parallel runs tasks in parallel across CPU cores. It's faster than xargs and easier than writing a job queue. Here's when and how to use it.

LVM Advanced: Snapshots, Thin Provisioning, and Not Losing Your Data

Master LVM snapshots and thin provisioning on Linux. Learn to create, use, and merge snapshots for backups, and over-provision storage safely.

SSH Hardening: Lock Down Remote Access Without Locking Yourself Out

Harden SSH properly: disable password auth, switch to Ed25519 keys, configure sshd_config, set up SSH certificates with step-ca, add 2FA, and configure ProxyJump for bastion hosts.

trap in Bash: Clean Up When Your Script Dies

Use trap EXIT to clean up temp files, INT/TERM for graceful shutdown, and ERR for errors. Stop your bash scripts from leaving messes when they die.

Debugging Bash Scripts: set -x and Beyond

set -x prints every command before it runs. Add PS4 for context. Use trap for cleanup. Here's the toolkit every bash debugger needs.

Word Splitting: The Bash Gotcha That Corrupts Filenames

Unquoted bash variables split on IFS and quietly break loops, file ops, and filenames with spaces. Here's why it happens and how to always quote right.