Learn to automate tasks with bash shell scripts. Master variables, conditionals (if/else), loops (for/while), functions, and command-line arguments to create powerful automation scripts.

Learning Objectives

Create and execute bash scripts

Use variables and command-line arguments

Implement conditionals with if/else

Write for and while loops

Define and call functions

Build practical automation scripts

Step 1

Create your first shell script

Write a simple bash script with shebang and basic commands.

Commands to Run

cd ~

mkdir scripting-practice && cd scripting-practice

cat > hello.sh << 'EOF'
#!/bin/bash
echo "Hello, World!"
echo "Today is $(date +%A)"
EOF

cat hello.sh

chmod +x hello.sh

./hello.sh

What This Does

#!/bin/bash is shebang (tells system to use bash). echo prints messages. $(command) runs command and uses output. chmod +x makes script executable. ./ runs script in current directory.

Expected Outcome

Script created with shebang and two echo lines. chmod makes it executable. ./hello.sh prints greeting and current day name.

Pro Tips

1
#!/bin/bash MUST be first line (shebang)
2
$(command) executes command and substitutes output
3
chmod +x required before running script
4
./script.sh runs script in current dir
5
Scripts are just files with commands
6
Use .sh extension by convention

Common Mistakes to Avoid

⚠️Forgetting shebang (may work but not portable)
⚠️Not making script executable with chmod +x
⚠️Trying to run script.sh instead of ./script.sh

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204 — Shell Scripting Basics