Installing Claude Code CLI on Your Server

This guide will help you install and set up Claude Code (the AI coding assistant CLI) on your server.

Prerequisites

Installation Methods

Method 2: Download Binary (Alternative)

If you don’t want to use npm:

# Download the latest Linux binary
cd /tmp
curl -L https://github.com/anthropics/claude-code/releases/latest/download/claude-linux-x64 -o claude

# Make executable
chmod +x claude

# Move to system path
sudo mv claude /usr/local/bin/

# Verify installation
claude --version

Method 3: Build from Source (For Latest Features)

# Install git if not present
sudo apt install git

# Clone the repository
git clone https://github.com/anthropics/claude-code.git
cd claude-code

# Install dependencies
npm install

# Build
npm run build

# Link globally
sudo npm link

# Verify
claude --version

Configuration

Step 1: Get Anthropic API Key

  1. Go to https://console.anthropic.com/

  2. Sign in or create an account

  3. Navigate to API Keys

  4. Create a new API key

  5. Copy the key (starts with sk-ant-...)

Step 2: Configure Claude Code

# Set up authentication
claude auth login

# When prompted, paste your API key
# It will be stored securely in ~/.config/claude/

Or set the environment variable:

# Add to ~/.bashrc or ~/.bash_profile
export ANTHROPIC_API_KEY="sk-ant-your-key-here"

# Reload shell
source ~/.bashrc

Step 3: Verify Configuration

# Test Claude Code
claude --help

# Try a simple command
claude "what is 2+2"

Basic Usage

Interactive Chat Mode

# Start interactive session
claude

# You'll see a prompt where you can chat with Claude
# Type your questions and press Enter
# Type 'exit' or Ctrl+D to quit

One-off Commands

# Ask a question
claude "explain how git works"

# Code generation
claude "write a python function to reverse a string"

# File analysis
claude "analyze this code" < script.py

# Help with commands
claude "how do I find large files in linux"

Working with Files

# Analyze a file
claude --file mycode.py "explain what this code does"

# Multiple files
claude --file file1.js --file file2.js "find bugs in these files"

# Edit files (creates backup)
claude --edit mycode.py "add error handling to all functions"

Code Mode (for coding tasks)

# Start in code mode
claude code

# Or use inline
claude code "create a REST API server in Python"

Advanced Configuration

Custom Configuration File

Create ~/.config/claude/config.json:

{
  "model": "claude-3-5-sonnet-20241022",
  "maxTokens": 4096,
  "temperature": 1.0,
  "defaultProject": "~/projects"
}

Set Default Model

# Use Opus (most capable)
claude config set model claude-3-opus-20240229

# Use Sonnet (balanced)
claude config set model claude-3-5-sonnet-20241022

# Use Haiku (fastest/cheapest)
claude config set model claude-3-haiku-20240307

Enable Features

# Enable MCP (Model Context Protocol) servers
claude config set mcp.enabled true

# Set workspace
claude config set workspace ~/paperman

# Enable auto-save
claude config set autosave true

Using Claude Code with Paperman Development

Analyze Paperman Code

# Navigate to paperman directory
cd ~/paperman

# Start Claude Code in the paperman directory
claude code

# Ask questions about the code
# "explain how the search server works"
# "add logging to the PDF conversion function"
# "review this code for security issues"

Git Integration

# Review changes before commit
git diff | claude "review these changes for bugs"

# Generate commit messages
git diff --staged | claude "write a conventional commit message for these changes"

# Code review
claude --file searchserver.cpp "review this code and suggest improvements"

Debugging Help

# Analyze error logs
tail -100 /var/log/paperman.log | claude "what's causing this error"

# Debug compilation errors
make 2>&1 | claude "explain and fix these compilation errors"

SSH Usage (Running Claude on the Server from Dev Machine)

If you want to use Claude on the server while working from your dev machine:

Option 1: SSH and Run

# From dev machine
ssh your-server
claude "your question here"

Option 2: SSH with Command

# Run Claude command over SSH
ssh your-server "claude 'explain how systemd works'"

Option 3: tmux/screen Session

# On the server, start a persistent session
tmux new -s claude
claude code

# Detach with Ctrl+B, D
# Reattach later with:
tmux attach -t claude

Troubleshooting

“command not found: claude”

# Check if installed
which claude

# If npm install, check npm global path
npm config get prefix

# Add to PATH if needed
export PATH="$PATH:$(npm config get prefix)/bin"

# Add to ~/.bashrc to make permanent
echo 'export PATH="$PATH:'"$(npm config get prefix)/bin"'"' >> ~/.bashrc

“API key not found”

# Check environment variable
echo $ANTHROPIC_API_KEY

# Or reconfigure
claude auth login

# Or set in config
claude config set apiKey "sk-ant-your-key-here"

“Permission denied”

# Fix permissions on config directory
chmod 700 ~/.config/claude
chmod 600 ~/.config/claude/*

“Module not found” (if using npm)

# Reinstall
sudo npm uninstall -g @anthropic-ai/claude-code
sudo npm install -g @anthropic-ai/claude-code

# Clear npm cache if issues persist
sudo npm cache clean --force

Rate Limits / API Errors

# Check API usage at console.anthropic.com
# You may need to add credits to your account

# Reduce request rate
claude config set rateLimit 10

# Use cheaper model
claude config set model claude-3-haiku-20240307

Useful Aliases

Add to ~/.bashrc for convenience:

# Quick Claude commands
alias ask='claude'
alias code-review='claude "review this code for bugs, security issues, and best practices"'
alias explain='claude "explain this in simple terms"'
alias debug='claude "help me debug this issue"'

# Git helpers
alias commit-msg='git diff --staged | claude "write a concise commit message"'
alias review-pr='git diff main | claude "review these changes as if doing a PR review"'

# System helpers
alias logs-analyze='sudo journalctl -n 100 | claude "analyze these logs for errors"'
alias disk-help='claude "I need help managing disk space on linux"'

Reload:

source ~/.bashrc

Security Best Practices

Protect Your API Key

# Never commit API key to git
echo "ANTHROPIC_API_KEY=*" >> .gitignore
echo ".config/claude/" >> .gitignore

# Use environment variables
# Add to ~/.bashrc (not to git repo)
export ANTHROPIC_API_KEY="sk-ant-..."

# Restrict permissions on config
chmod 600 ~/.config/claude/config.json

Sensitive Data

  • Don’t send sensitive credentials or passwords to Claude

  • Be careful with proprietary code

  • Review responses before applying code changes

  • Use --dry-run flags when available

Cost Management

Monitor Usage

Cost-Saving Tips

# Use shorter context
claude --max-tokens 1000 "quick question"

# Use Haiku for simple tasks
claude --model claude-3-haiku-20240307 "simple question"

# Avoid large file uploads
# Instead of uploading entire files, paste relevant snippets

Updating Claude Code

Update via npm

# Update to latest version
sudo npm update -g @anthropic-ai/claude-code

# Check current version
claude --version

# Check for updates
npm outdated -g @anthropic-ai/claude-code

Update via binary

# Download latest version
cd /tmp
curl -L https://github.com/anthropics/claude-code/releases/latest/download/claude-linux-x64 -o claude
chmod +x claude
sudo mv claude /usr/local/bin/claude

# Verify
claude --version

Integration with paperman-server Development

Example Workflow

# 1. Start working on paperman
cd ~/paperman

# 2. Start Claude Code
claude code

# 3. Ask for help
# > "I want to add rate limiting to the search server"
# > "Review searchserver.cpp for security issues"
# > "Help me optimize the PDF conversion performance"

# 4. Apply changes Claude suggests
# Claude can directly edit files with your permission

# 5. Test changes
make && ./paperman-server test

# 6. Get help with errors
# If errors occur, paste them to Claude:
# > "I'm getting this compilation error: [paste error]"

# 7. Commit with AI-generated message
git diff --staged | claude "write a commit message"

Quick Reference

Essential Commands

# Interactive mode
claude

# Code mode
claude code

# One-off question
claude "your question"

# Help
claude --help

# Version
claude --version

# Configuration
claude config list
claude config set key value
claude config get key

Common Tasks

# Explain code
claude --file mycode.cpp "explain this code"

# Debug error
claude "explain this error: [paste error]"

# Generate code
claude "write a bash script to backup a directory"

# Review changes
git diff | claude "review these changes"

# Documentation
claude "write documentation for this function" < function.cpp

Next Steps

After installation:

  1. ✅ Test with simple questions

  2. ✅ Try analyzing paperman code

  3. ✅ Use for debugging

  4. ✅ Generate commit messages

  5. ✅ Code reviews

  6. ✅ Add useful aliases

Resources

Support

If you encounter issues:

  1. Check https://github.com/anthropics/claude-code/issues

  2. Read the troubleshooting section above

  3. Check API status at https://status.anthropic.com/

  4. Review usage/billing at console.anthropic.com

You’re all set to use Claude Code on your server! 🎉