Bash scripting is critical for many tech roles, especially in Linux system administration, DevOps, and software engineering.
If you're hiring someone for any Linux-orientated role, you will want your team members to have a solid understanding of Bash scripting and be able to solve common script task problems.
About Bash
Bash is a shell scripting language that allows you to interact with a Unix-like operating system via commands. It is a command-line tool that helps automate tasks, manage servers, and streamline processes on Unix-based systems like Linux and macOS. Whether it's running a quick script to clean up files or managing complex server deployments, Bash is super useful and should be a core skill in these areas.
Bash scripts can do everything from manipulating files to running programs automatically, saving time and effort.
For tech teams, Bash is a favorite because it's lightweight, works on many systems, and is great for automating tasks like file management, server monitoring, and system backups. It's used in various environments, from web hosting to cloud services, and is especially important in DevOps and system administration roles.
Must-have technical skills for Bash Developers
Here are the essential skills a good Bash developer should have:
- Bash scripting: They should be comfortable writing, editing, and running Bash scripts, know basic syntax like loops, conditionals, and functions, and have experience debugging and updating scripts. Bash provides command-line tools such as parameter expansion, piping, redirection, and signal handling.
- File and process management: They need to know how to work with files (e.g., copying, moving, renaming) and manage running processes on the system.
- Unix/Linux commands: A good Bash developer should be fluent in common Unix commands like grep, sed, awk, and find.
- Regular expressions: These are useful for finding text patterns and automating tasks involving data extraction or search operations.
- Git and version control: They should know how to manage code using Git, especially if collaborating with a team.
- Automation tools: Experience using cron jobs for task scheduling or setting up automated backups is key.
Nice-to-have technical skills
While not essential, these extra skills can help a Bash developer stand out:
- Knowledge of other scripting languages: They must have experience with Python, or Perl can be handy for more complex automation tasks. Windows environments tend to use PowerShell to perform similar functionality.
- CI/CD pipeline tools: They should be familiar with tools like Jenkins or GitLab CI for automating builds and deployments.
- Infrastructure as Code (Iaac): Infra and configuration management tools such as Ansible and Terraform are often used for infra automation.
- Containerization (Docker/Kubernetes): A solid understanding of automating container and cloud service tasks is a bonus.
- Cloud automation: Experience with AWS CLI, Google Cloud CLI, or similar tools for managing cloud environments will also be useful.
Interview questions for Bash Developers
To help you assess a candidate's Bash skills, here are some interview questions you could ask along with the kind of answers you should expect:
1. What does #!/bin/bash mean in a script?
Example answer: It's called a "she-bang” (combination of "sharp" (#) and "bang" (!) and tells the system to run the script using the Bash shell at the top of the script.
2. How do you check if a file exists in Bash?
Example answer: Using an if statement with -f. The example below will check if a file exists. You can also use -d to check for a directory or -e to check for any file type (including symbolic links)
if [ -f "proxify.txt" ]; then
echo "File exists."
else
echo "File does not exist."
fi
3. How do you handle errors in Bash scripts?
Example answer: You can use set -e to make the script stop if any command fails or check each command’s exit status using $?.
4. What’s the difference between $ and $@
Example answer: Both represent all script arguments, but $* treats them as a single string, while $@ keeps them as separate arguments.
5. How do you find and delete files older than 7 days in a directory?
Example answer: Using the find command in bash. This is used quite often for file archive and cleanup operations. You could show this command to the candidate and ask them when it would be used.
find /path/to/dir -type f -mtime +7 -exec rm {} \;
6. What are pipes in Bash and how do they work?
Example answer: Pipes (|) take the output of one command and use it as input for another. For example, ls | grep ".txt" lists all .txt files.
7. How would you read a file line by line in Bash?
Example answer: You can use a while loop
while IFS= read -r line; do
echo "$line"
done < file.txt
8. What does exit 0 mean in a script?
Example answer: It means the script finished successfully. Non-zero numbers usually indicate an error. If you intend to return an error from the script then usually you would exit 1; (non 0 return value).
9. How do you run a command in the background in Bash?
Example answer: By adding & at the end of the command, like my_command &.
10. What are some common security mistakes to avoid in Bash scripting?
Example answer: Avoid hardcoding sensitive data, validate inputs to prevent injection attacks, and ensure scripts are run with the right permissions and under the right user.
Industries and applications of Bash
Bash is used across different industries, but it’s most common where Linux or macOS servers are involved. Here are some areas where Bash developers are especially valuable:
- System administration: Automating day-to-day tasks like backups, updates, and server monitoring.
- DevOps and Cloud: Setting up and managing CI/CD pipelines, automating deployments, and managing cloud infrastructure (e.g., AWS, Google Cloud).
- Cybersecurity: Writing scripts for scanning vulnerabilities, monitoring logs, and securing systems.
- Web hosting: Automating server configurations and deployment processes for websites.
- Network administration: Automating network scripts and configuration on Linux systems.
Customers with Linux-based infrastructure or one that uses cloud services heavily can really benefit from a skilled Bash developer, who can create scripted workflows and improve efficiency.
Summary
In summary, a good Bash developer is someone comfortable working in Unix/Linux environments, knows how to automate tasks, and understands the importance of security. They should also be familiar with core Bash scripting, system management, and automation tools.
While nice-to-have skills like experience with cloud platforms or other scripting languages are great, the core focus should be their ability to write clean, efficient, and secure scripts.
Bash is a core skill in Linux administration, and most Linux engineers should have it as a core skill.
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