Week 1 Installation Guide

Prerequisites: You should have completed the Week 0 Installation Guide and have SSH access to CLEAR.

This week focuses on shell scripting, so you’ll need tools for writing, testing, and debugging bash scripts.

Required Tools

1. ShellCheck (Script Linter)

ShellCheck is essential for learning bash. It catches common mistakes and suggests improvements.

macOS

brew install shellcheck

Linux (Ubuntu/Debian)

sudo apt install shellcheck

Windows (WSL)

sudo apt install shellcheck

CLEAR

ShellCheck should already be available. Test with:

shellcheck --version

If not installed, you can download the binary:

# In your home directory on CLEAR
cd ~
wget https://github.com/koalaman/shellcheck/releases/download/stable/shellcheck-stable.linux.x86_64.tar.xz
tar -xf shellcheck-stable.linux.x86_64.tar.xz
mkdir -p ~/.local/bin
mv shellcheck-stable/shellcheck ~/.local/bin/

Then add to your ~/.bashrc:

export PATH="$HOME/.local/bin:$PATH"

Verify Installation

shellcheck --version

2. Text Editor

You need a way to write scripts. Choose one of the following:

Option A: nano (Easiest for beginners)

Already installed on most systems. No setup needed.

nano myscript.sh

Basic commands:

  • Ctrl+O - Save
  • Ctrl+X - Exit
  • Ctrl+K - Cut line
  • Ctrl+U - Paste

Option B: vim (More powerful, steeper learning curve)

Already installed. We’ll cover vim in Week 3, but you can start learning now.

vim myscript.sh

Survival guide:

  • Press i to enter insert mode
  • Type your script
  • Press Esc to exit insert mode
  • Type :wq and press Enter to save and quit
  • Type :q! and press Enter to quit without saving

If you prefer working on CLEAR with a GUI editor:

  1. Install VS Code
  2. Install the “Remote - SSH” extension
  3. Connect to CLEAR through VS Code

Benefits:

  • Syntax highlighting
  • Auto-completion
  • Integrated terminal
  • ShellCheck integration

Optional (But Useful) Tools

bat (Better cat with syntax highlighting)

Useful for viewing scripts with syntax highlighting.

macOS

brew install bat

Linux

sudo apt install bat

Note: On some systems, the command is batcat instead of bat due to naming conflicts.

Usage:

bat myscript.sh  # View script with highlighting

tldr (Simplified man pages)

Quick reference for commands instead of full man pages.

macOS

brew install tldr

Linux

sudo apt install tldr

Usage:

tldr tar    # Quick examples for tar
tldr find   # Quick examples for find

Verification

Run these commands to verify your setup:

# Check bash version (should be 4.0+)
bash --version

# Check shellcheck
shellcheck --version

# Check text editor (choose one)
nano --version
vim --version

# Test script creation
echo '#!/usr/bin/env bash' > test.sh
echo 'echo "Hello, Week 1!"' >> test.sh
chmod +x test.sh
./test.sh

# Test shellcheck
shellcheck test.sh

# Clean up
rm test.sh

Expected output:

$ ./test.sh
Hello, Week 1!

$ shellcheck test.sh
# No output means no errors!

Setting Up Your Environment

Create a scripts directory

Good practice: keep scripts organized.

mkdir -p ~/scripts
cd ~/scripts

Add scripts to PATH (Optional)

If you want to run your scripts from anywhere:

# Add to ~/.bashrc (or ~/.zshrc)
export PATH="$HOME/scripts:$PATH"

Then reload:

source ~/.bashrc

Now scripts in ~/scripts can be run from anywhere (if executable).

ShellCheck Integration

Using ShellCheck

Always check your scripts before running:

shellcheck myscript.sh

Example output:

In myscript.sh line 3:
rm $file
   ^---^ SC2086: Double quote to prevent globbing and word splitting.

Fix the issue:

rm "$file"  # Add quotes

Ignore specific warnings (when you know what you’re doing):

# shellcheck disable=SC2086
rm $file  # Intentionally unquoted

Common Issues

“Permission denied” when running script

Problem:

$ ./myscript.sh
-bash: ./myscript.sh: Permission denied

Solution:

chmod +x myscript.sh

“No such file or directory” with shebang

Problem:

#!/bin/bash

Works on some systems but not others.

Solution: Use the portable version:

#!/usr/bin/env bash

Scripts work locally but not on CLEAR

Problem: Different bash versions or missing tools.

Solution: Always test on CLEAR before submitting:

ssh clear
cd ~/path/to/scripts
./myscript.sh

Editor Configuration

nano Configuration

Create ~/.nanorc:

set autoindent
set tabsize 4
set tabstospaces
include /usr/share/nano/*.nanorc

vim Configuration (Basic)

Create ~/.vimrc:

" Basic settings for shell scripting
syntax on
set number
set autoindent
set tabstop=4
set shiftwidth=4
set expandtab

Testing Your Setup

Create and run this test script:

#!/usr/bin/env bash
# test_setup.sh - Verify Week 1 setup

set -euo pipefail

echo "Testing Week 1 setup..."

# Test 1: Bash version
echo -n "Bash version: "
bash --version | head -1

# Test 2: ShellCheck
echo -n "ShellCheck: "
if command -v shellcheck &> /dev/null; then
    echo "✓ Installed"
else
    echo "✗ Not found - Install shellcheck!"
    exit 1
fi

# Test 3: Text editor
echo -n "Text editor: "
if command -v nano &> /dev/null; then
    echo "✓ nano available"
elif command -v vim &> /dev/null; then
    echo "✓ vim available"
else
    echo "✗ No editor found"
    exit 1
fi

# Test 4: Script permissions
echo -n "File permissions: "
if [[ -x "$0" ]]; then
    echo "✓ Script is executable"
else
    echo "✗ Script not executable (run: chmod +x $0)"
fi

echo ""
echo "Setup complete! You're ready for Week 1."

Save as test_setup.sh, make executable, and run:

chmod +x test_setup.sh
./test_setup.sh

Quick Reference Card

Save this for quick access:

# Make script executable
chmod +x script.sh

# Run script
./script.sh

# Check script for errors
shellcheck script.sh

# Debug script (show commands as they execute)
bash -x script.sh

# Edit script
nano script.sh    # or vim script.sh

# View script with syntax highlighting
bat script.sh     # if installed

What’s NOT Required

You don’t need to install:

  • Complex IDEs
  • Git GUI tools (command line is fine)
  • Docker (not until later weeks)
  • Any programming languages besides bash

Keep it simple. You already have everything you need to write powerful scripts.

Next Steps

  1. Verify your installation with the test script above
  2. Complete the Week 1 homework
  3. Experiment with ShellCheck on your scripts
  4. Consider learning vim basics (we’ll cover it in Week 3)

Questions? Bring them to office hours or post in the class forum.

Resources

Remember: The goal is to write working scripts, not to master every tool perfectly. Start simple and build up!