Master the Command Line Like a Pro

If you’re preparing for the Linux Foundation Certified SysAdmin (LFCS) exam, knowing how to write and understand shell scripts is essential. Whether you’re automating routine tasks or solving exam challenges, shell scripting is your secret weapon for working smarter in Linux.

In this hands-on guide, we’ll cover the shell scripting basics you need to know for the LFCS, with examples, explanations, and practice tips to help you get exam-ready.

Why Shell Scripting Matters for LFCS

Shell scripts are used to:

Automate system admin tasks (user management, backups, updates)
Configure services and startup behavior
Manage permissions and scheduled tasks (cron jobs)

🧪 The LFCS exam may test your ability to:

Create or edit basic scripts
Use conditionals (if/else)
Loop through files
Pass and use command-line arguments
Redirect output

What is a Shell Script?

A shell script is a text file that contains a series of Linux commands. It’s executed by a shell like Bash.

Basic structure:

#!/bin/bash
echo "Hello, World!"

#!/bin/bash is the shebang—it tells the system to use Bash to interpret the script.
The rest are the same commands you’d type in a terminal.

To run it:

chmod +x script.sh
./script.sh

Key Scripting Concepts for LFCS

1. Variables

name="LinuxUser"
echo "Welcome, $name!"

2. Input and Arguments

echo "Hello $1"

Run with: ./greet.sh John

3. Conditional Statements

if [ "$1" == "admin" ]; then
  echo "Access granted."
else
  echo "Access denied."
fi

4. Loops

for file in *.txt; do
  echo "Found file: $file"
done

5. Functions

greet() {
  echo "Hello, $1!"
}
greet Alice

6. Redirection and Pipes

echo "Logging output" >> log.txt
cat /etc/passwd | grep root

7. Exit Codes

if [ $? -eq 0 ]; then
  echo "Success"
else
  echo "Failure"
fi

Scripting Topics That Often Appear in LFCS

✅ File manipulation with mv, cp, rm, and find
✅ Using cron or at for scheduling
✅ Reading from input using read
✅ Parsing with cut, awk, and sed
✅ Creating and managing scripts under /usr/local/bin/

📘 Recommended Book: The Linux Command Line by William E. Shotts

Practice Tips for Shell Scripting

Create a /scripts directory in your home folder to practice
Automate something real: backups, renaming files, etc.
Use man bash and help for built-in docs
Try challenges at OverTheWire: Bandit

Example Practice Script:

#!/bin/bash
# Batch rename .txt files to .bak
for file in *.txt; do
  mv "$file" "${file%.txt}.bak"
done

Internal Links

External Links

FAQ

Do I need to memorize scripts for the LFCS exam?

No. It’s more important to understand how scripts work and be able to write or fix simple scripts under pressure.

Which shell does the LFCS use?

The exam uses Bash by default unless otherwise specified.

Are scripting questions multiple choice?

No. The LFCS exam is hands-on. You’ll write real commands and potentially edit real scripts.

How much scripting is on the LFCS?

Expect at least a few tasks involving automation, conditions, or scheduling via shell scripts.

Call to Action

🚀 Ready to crush the LFCS?

📘 Start scripting today with The Linux Command Line and build a routine with daily practice.

🎓 Or enroll in Linux Foundation’s official LFCS prep course.

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