I spent five years on the AWS Billing team. The hardest problem I tackled was detecting when customers used AWS services but weren't charged correctly. This post walks through how I designed a system that reduced charge discrepancies by **300x** and eliminated **230 million** monthly false positives. The Problem # AWS billing is trickier than it looks. When a customer launches an EC2 instance, writes to S3, or queries DynamoDB, each action generates a usage record. These records flow through a pipeline that calculates charges based on the customer’s pricing plan, region, and service tier.
After years of refining my terminal workflow, I've landed on a stack I genuinely enjoy using every day: **Ghostty** as the terminal emulator, **tmux** with **sesh** for session management, and **Neovim** with **LazyVim** for editing. Everything runs on macOS (Apple Silicon) with a consistent Catppuccin Mocha theme across all tools.
I've been gradually replacing classic Unix tools with modern alternatives, mostly written in Rust . After a year of daily use, these aren't experiments anymore. They're muscle memory. The Replacements # Classic Modern Why cat bat Syntax highlighting, line numbers, git integration ls eza Icons, git status, tree view, color-coded grep ripgrep 10x faster, respects .gitignore, smart case find fd Simpler syntax, respects .gitignore, colored output cd zoxide Learns your habits, fuzzy matching sed sd Intuitive regex syntax, no escaping nightmare du dust Visual directory size with a tree view df duf Colorful, filterable disk usage top btop Beautiful TUI with mouse support, per-core graphs ps procs Colorized, searchable, tree view history atuin Encrypted sync, full-text search, workspace filtering Setting Up Aliases # In my .zshrc, I alias the classics to their replacements so the transition is invisible:
Every developer eventually reaches the point where their configs become too valuable to lose. Here's how I use **yadm** to manage my macOS dotfiles with automated testing, daily maintenance, and a pre-commit workflow that keeps everything in check. For me, the turning point was spending a weekend setting up a new MacBook and realizing I couldn’t reproduce my environment reliably. That’s when I started managing my dotfiles properly.