shell-utilities

A collection of zsh / iTerm2 shell scripts for developer productivity I've created and have been using for some time now. Each script is self-contained and ships with a built-in installer that appends the necessary source line to your ~/.zshrc.

Contents

shell-utils/
├── aliases-injected.sh       # Installs aliases inline into ~/.zshrc
├── aliases-mapped.sh         # Installs a source pointer to an external aliases.sh
├── functions.sh              # Developer utility functions
├── claude-keepalive/
│   └── keepalive.sh          # Keeps a Claude.ai usage window active

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Installation

Every script supports a one-shot installer. Clone or download this repo, then run any combination of the following. All installers are idempotent — running them twice will not create duplicate entries.

# Make scripts executable (once)
chmod +x aliases-injected.sh aliases-mapped.sh functions.sh

# Install each script you want
./aliases-injected.sh install
./aliases-mapped.sh   install
./functions.sh        install

# Reload your shell
source ~/.zshrc

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claude-keepalive/keepalive.sh

Pre-warms a Claude.ai usage window so that when you actually sit down to code, a large portion of the ~4–5 hour window has already elapsed — meaning your next window after hitting the limit will be available sooner.

How it works: The claude CLI (Claude Code) shares the same usage session as the Claude.ai web UI. The script sends a minimal "Hi" ping on a configurable interval using the haiku model, which costs the fewest tokens.

Requirements

• claude CLI installed and authenticated (claude auth login)
• macOS (caffeinate is used to prevent the machine from sleeping between intervals)

Usage

cd claude-keepalive

# Foreground (Ctrl+C to stop)
./keepalive.sh

# Background with log
nohup ./keepalive.sh >> keepalive.log 2>&1 &

# Background, fully detached
./keepalive.sh & disown

# Stop a backgrounded instance
pkill -f keepalive.sh

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aliases-injected.sh

Appends all alias definitions directly into ~/.zshrc as a heredoc block. Best if you want the aliases to be visible when you open your rc file without needing a second file on disk.

./aliases-injected.sh install

Aliases

Node / npm

Alias	Expands to
dev	nvm use (if .nvmrc present) + npm run dev
build	nvm use + npm run build
start	nvm use + npm start
test	nvm use + npm run test
run	nvm use + npm run
ni	nvm use + npm i
nci	nvm use + npm ci
nil	nvm use + npm i --legacy-peer-deps
use	nvm use
nv	node -v && npm -v
serve	npx serve .

System

Alias	Expands to
cls	clear
reload	source ~/.zshrc (or ~/.bashrc)
path	Print each $PATH entry on its own line
ports	lsof — list all listening TCP ports
ip	Local IP via ipconfig getifaddr en0
myip	Public IP via ifconfig.me
weather	Current weather via wttr.in
brewup	brew update && brew upgrade && brew cleanup

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aliases-mapped.sh

Adds a source pointer in ~/.zshrc pointing to a separate aliases.sh file in the same directory. Useful when you want to keep your rc file clean and manage aliases in a dedicated, version-controlled file.

Note: You need to create aliases.sh alongside this script — it is the file that will be sourced. The aliases listed above (same set as aliases-injected.sh) can be placed there.

./aliases-mapped.sh install

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functions.sh

Utility shell functions that extend what aliases can do. Sourced into your shell — no subshell spawned.

./functions.sh install

Navigation

Function	Description
mkcd <dir>	mkdir -p the directory and immediately cd into it
up [n]	Go up n directory levels (default: 1)

File & Archive

Function	Description
extract <file>	Auto-detect format and extract any archive: .tar.gz, .zip, .7z, .rar, .zst, and more
backup <file>	Create a timestamped copy — e.g. config.json.bak.2026-02-20T09:15:00
sized [dir]	Disk usage of a directory's contents, sorted largest-first (top 30)

Text & Data

Function	Description
json [file]	Pretty-print JSON from a file, a pipe, or stdin
b64encode <str>	Base64-encode a string
b64decode <str>	Base64-decode a string or piped input
find-replace <old> <new> [dir] [glob]	Recursive in-place sed across a directory tree

# Examples
echo '{"name":"ada"}' | json
b64encode "hello world"
find-replace "localhost:3000" "localhost:8080" ./src "*.ts"

Networking

Function	Description
kill-port <port>	Find and kill -9 whatever process is listening on a TCP port
headers <url>	Show HTTP response headers for a URL (via curl -sI)

Process & Performance

Function	Description
timeit <cmd…>	Run any command and report its wall-clock time in ms and seconds

timeit npm run build
# ⏱  Finished in 4821ms (4s)

Notes

A lightweight plain-text note system backed by ~/notes.md. Override the path with export NOTE_FILE=~/path/to/notes.md.

Function	Description
note <text>	Append a timestamped bullet to ~/notes.md
note	Open ~/notes.md in $EDITOR
notes	Show the last 20 entries
notes <query>	Case-insensitive grep through all notes

note "Bump Node to 22 before deploying"
notes "deploy"

Math

Function	Description
calc <expr>	Evaluate an expression via Python — supports decimals, sqrt, pi, etc.

calc "sqrt(144) / 2"   # 6.0
calc "2 ** 10"         # 1024

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Configuration

Edit the variables at the top of keepalive.sh:

Variable	Default	Description
INTERVAL_MINUTES	30	Minutes between pings
PING_MESSAGE	"Hi"	Message sent each ping
PING_MODEL	"haiku"	Claude model to use

---

Requirements

Tool	Required by	Install
zsh	All scripts	macOS built-in
nvm	npm aliases	nvm-sh/nvm
python3	json, calc	macOS built-in
curl	headers, myip, weather	macOS built-in
brew	brewup	brew.sh
claude CLI	keepalive.sh	claude.ai/code