SSH Cheat Sheet

SSH 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 npm Cheat Sheet and sed Cheat Sheet.

Setup and Installation

Goal: Verify installation and CLI metadata

# Resolve command path from current shell
command -v ssh

# Print installed version to confirm runtime
ssh --version

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

Goal: Install or upgrade the tool on a workstation

# Install package with Homebrew on macOS
brew install openssh

# Upgrade to the latest available package
brew upgrade openssh

# Re-check version after upgrade
ssh --version

Goal: Run day-to-day commands

# Generate an Ed25519 SSH keypair
ssh-keygen -t ed25519 -C "you@example.com"

# Copy public key to remote server
ssh-copy-id user@server.example.com

# Open remote shell session
ssh user@server.example.com

# Create local port-forward tunnel
ssh -L 5432:localhost:5432 user@db-host.example.com

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
ssh --help > docs/cli/ssh-help.txt

# Search help output for a keyword
rg "config|auth|deploy" docs/cli/ssh-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-ssh.sh <<'SH'
#!/usr/bin/env bash
set -euo pipefail
ssh --version
ssh --help >/dev/null
SH

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

Configuration and Environment

Goal: Pin environment variables for predictable runs

# Define environment profile for local commands
export SSH_PROFILE=dev

# Persist profile in local shell configuration
echo 'export SSH_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 ssh

# Exit quickly if command is unavailable
ssh --version

Debugging and Troubleshooting

Goal: Collect diagnostics when commands fail

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

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

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

Common Gotchas

• Pin SSH 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

• npm Cheat Sheet — daily npm commands and production-ready examples.
• sed Cheat Sheet — daily sed commands and production-ready examples.
• Ansible Cheat Sheet — daily Ansible commands and production-ready examples.