Shell programming or shell scripting consists of most of the features that modern programming languages have to offer. Any script, simple to complex, can be developed using Shell scripting. It is a series of UNIX commands written to accomplish a particular task using a plain text file. Tasks of day-to-day life can be automated with the help of shell scripting. Â.
If you are new to the concepts of Unix, shell, and Perl, read it here. If you know how to use shell scripting and are going to be interviewed for a job that involves it, this article with the best shell scripting interview questions will help you get ready.
Bash RC file, also known as .bashrc, is a crucial part of configuring your shell environment on Linux and other Unix-based operating systems. As a developer working in these environments, having a strong grasp of how to customize and utilize .bashrc is key to enhancing your productivity.
We’ll go over some of the most common and in-depth bash RC file interview questions you’re likely to be asked during the hiring process in this detailed guide. Whether you’re a beginner who wants to learn the basics or an experienced pro who wants to brush up on your skills, keep reading to find out how to handle even the hardest problems. bashrc queries.
Overview of the .bashrc File
But first what exactly is the bash RC file?
The . The.bashrc file is a script that runs every time you start a new case of bash. It lets you make changes and adjustments to your command line interface (CLI), such as
- Setting environment variables
- Creating aliases for common commands
- Defining shell functions
- Changing CLI colors and prompt style
By tweaking your .bashrc file, you can streamline repetitive tasks, optimize workflows, and tailor the interface to suit your needs
Now let’s look at some common interview questions about it.
Basic .bashrc Interview Questions
Q Where is the bashrc file located on a Linux system?
A: The .bashrc file is located in the user’s home directory and is named .bashrc. The full path is ~/.bashrc. The dot (.) indicates it is a hidden file.
Q: When is the .bashrc file executed or sourced?
A: The .bashrc file is executed every time a new interactive non-login shell session is opened. For example, whenever you open a new terminal window.
Q: What is the difference between .bashrc and .bash_profile files?
A: .bashrc is executed for every new non-login shell while .bash_profile is only executed for login shells. .bashrc is used to set up an interactive environment while .bash_profile handles global settings and environment variables.
Q: How can you reload changes made to .bashrc without restarting terminal?
A: Use the source command like source ~/.bashrc to reload the .bashrc file and apply any changes immediately in the current shell.
Q: What are some common customizations made via the .bashrc file?
A: Common customizations include setting environment variables, creating aliases/shortcuts for commands, adding directories to PATH, defining shell functions, customizing the prompt, and changing colors/themes.
Q: Where should you put commands that need to be run only once at login?
A: Commands that need to execute only once at login should be added to the .bash_profile file instead of .bashrc. .bash_profile is sourced only for login shells.
Intermediate .bashrc Questions
Q: How can you debug issues with your .bashrc file?
A: Methodically comment out portions of the file and source .bashrc after each change to isolate the problem. Check for syntax errors. Start with a fresh unmodified .bashrc and gradually add customizations back till issue reappears.
Q: What is the best way to modify the PATH variable in .bashrc?
A: Append new paths at the end of PATH instead of overwriting. For example: export PATH=$PATH:/my/new/path. This preserves existing paths.
Q: How do you set an environment variable in .bashrc available to all child processes?
A: Use the export keyword before defining the variable. For example: export MYVAR=value. This exports the variable to subshells.
Q: What is the disadvantage of defining conflicting aliases in .bashrc and .bash_profile?
A: The last file loaded takes precedence. If .bashrc and .bash_profile contain aliases with same name but different commands, the one in .bashrc will work for new shells while .bash_profile’s version will override in login shells.
Q: Can you show an example of creating a custom function via .bashrc?
A: Here is an example function that lists files recursively:
function lsr(){ ls -lR "$1"}To use: lsr foldername
Q: How can you customize or change the bash prompt using .bashrc?
A: Prompt can be customized by changing the PS1 variable. For example:
PS1="[$(tput bold)]u@h:w$ [$(tput sgr0)]"
Sets prompt to username@host:current_dir$
Advanced .bashrc Interview Questions
Q: What precautions should be taken while editing .bashrc file?
A: Always back up .bashrc before editing. Avoid adding insecure directories to PATH. Test changes in new shell before sourcing. Check for typos and syntax errors which could break existing sessions.
Q: Can you show an example of using conditional logic in .bashrc?
A: Here is an example to create alias for git only if git is installed:
if command -v git >/dev/null 2>&1; then alias gitpull='git pull origin main' fiQ: How can we run certain commands only for an interactive non-login shell?
A: Check the $- variable which contains current shell flags using an if condition:
if [[ $- == *i* ]]; then # interactive shell specific commandsfiQ: How do you troubleshoot “command not found” errors caused by .bashrc?
A: Check for typos in function names and aliases. Verify PATH is correctly set – missing directories can cause “command not found”. Test by uncommenting sections of .bashrc incrementally.
Q: Can you demonstrate how to customize tab completion via .bashrc?
A: Install bash-completion package. Enable it by sourcing /etc/bash_completion in .bashrc. Create completion scripts in /etc/bash_completion.d/ for custom commands.
Final Tips for Acing .bashrc Interview Questions
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Revise Linux fundamentals like processes, stdin/stdout, shell scripting etc. which aid in understanding the role of .bashrc
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Be thorough with the .bashrc source order, relationship between login vs non-login shells and dotfiles like .bash_profile.
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Practice creating sample .bashrc files from scratch and tweaking them to modify environment.
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Prepare examples demonstrating real-world customizations like aliases, PATH modification, prompt changing etc.
With this overview of some of the most common .bashrc file interview questions along with tips to master them, you’ll be well-prepared to impress interviewers with your in-depth knowledge. Keep these strategies in mind, and you’ll ace even the toughest questions confidently!
In what ways, shell script get input values?
a. By reading command: read -p “Destination backup Server: ” dest host
b. By parameters: ./script param1 param2
Shell Scripting Interview Questions for the Intermediate
Here are some intermediate level shell scripting interview questions!
What is bashrc file in Linux ||Linux Tutorial || Linux Interview Question
FAQ
What is the difference between [[ $string == efg * ]] and [[ $string == efg * ]]?
What is the name of the file in which shell programs are stored?
What is shell scripting in Linux for interview questions?
Is shell scripting hard?
What is the difference between Bash RC and bash_profile?
The .bashrc file is a shell script that Bash runs whenever it’s started interactively. It initializes an interactive shell session, setting up aliases, functions, and environment variables. The .bash_profile, on the other hand, is executed for login shells. It’s typically used to set environment variables such as PATH, USER, LOGNAME, and HOSTNAME.
What is the difference between bashrc and bash_profile?
Both .bashrc and .bash_profile are startup files containing shell commands. Moreover, they are hidden files located in the user’s home directory. Bash reads and executes .bash_profile when it’s invoked as an interactive login shell, whereas .bashrc is executed when Bash is invoked as an interactive non-login shell.
What is a bashrc file?
Technically, the .bashrc file is the configuration file for bash shell — used in Linux and macOS. It stands for the bash read command. When you open a new bash shell the script inside this file is executed from top to bottom. Each time you open the terminal (new bash session) .bashrc file read and execute each command inside the file.
How does bash_profile work?
In terms of their relationship, when a user logs in (via username and password), the system starts a login shell which reads .bash_profile. If this file calls the .bashrc file—common practice to avoid duplication of code—then the commands within .bashrc are also executed.
