Deno Cheat Sheet

Deno cheat sheet with real commands and snippets for setup, core workflows, debugging, and production-safe automation patterns. If you are working across tools, pair this with the TypeScript Cheat Sheet and Bun Cheat Sheet.

Setup and Installation

Goal: Verify installation and CLI metadata

# Resolve command path from current shell
command -v deno

# Print installed version to confirm runtime
deno --version

# Read top-level help before using subcommands
deno --help

Goal: Install or upgrade the tool on a workstation

# Install Deno using the official install script
curl -fsSL https://deno.land/install.sh | sh

# Confirm Deno installation
deno --version

Goal: Run day-to-day commands

# Run script with network and env permissions
deno run --allow-net --allow-env mod.ts

# Run tests in project
deno test

# Format source files
deno fmt

# Run linter checks
deno lint

Core Workflows

Goal: Capture command help for quick offline lookup

# Create docs folder for generated command references
mkdir -p docs/cli

# Write help output to a timestamped file
deno --help > docs/cli/deno-help.txt

# Search help output for a keyword
rg "config|auth|deploy" docs/cli/deno-help.txt

Goal: Wrap repetitive commands in a script

# Create scripts directory for local automation
mkdir -p scripts

# Write repeatable health-check script
cat > scripts/check-deno.sh <<'SH'
#!/usr/bin/env bash
set -euo pipefail
deno --version
deno --help >/dev/null
SH

# Make script executable and run it
chmod +x scripts/check-deno.sh && ./scripts/check-deno.sh

Configuration and Environment

Goal: Pin environment variables for predictable runs

# Define environment profile for local commands
export DENO_PROFILE=dev

# Persist profile in local shell configuration
echo 'export DENO_PROFILE=dev' >> ~/.zshrc

# Reload shell profile changes
source ~/.zshrc

Automation and CI

Goal: Add tool checks to CI pipeline

# Run lint/test/build in strict mode
set -euo pipefail

# Verify CLI exists before invoking workflow
command -v deno

# Exit quickly if command is unavailable
deno --version

Debugging and Troubleshooting

Goal: Collect diagnostics when commands fail

# Capture command output and exit code
deno --help > /tmp/deno-debug.log 2>&1; echo $?

# Inspect captured diagnostics
tail -n 80 /tmp/deno-debug.log

# Check current shell PATH entries
echo $PATH | tr ':' '\n'

Common Gotchas

• Pin Deno versions in CI so local and pipeline behavior match.
• Check tool authentication context before running write or deploy commands.
• Prefer non-interactive flags in scripts to avoid stalled jobs.
• Capture stderr logs in CI artifacts for faster incident triage.
• Keep secrets in environment variables, not committed scripts.

Related Sheets

• TypeScript Cheat Sheet — typed JavaScript project workflows.
• Bun Cheat Sheet — daily Bun commands and production-ready examples.
• curl Cheat Sheet — daily curl commands and production-ready examples.