What is Bash?
- Bash (Bourne Again Shell) is a command-line interpreter and scripting language used in Unix-based operating systems. It is an improved version of the Bourne Shell (sh).
How do you create a Bash script?
- Create a file with a .sh extension, add the shebang #!/bin/bash at the top, write commands, and give it execute permissions using chmod +x script.sh.
What is the significance of #!/bin/bash?
- It tells the system to use Bash as the interpreter for executing the script.
How do you execute a Bash script?
- Using ./script.sh (if it has execution permission) or bash script.sh.
What are positional parameters in Bash?
- $0 (script name), $1, $2, etc., represent arguments passed to the script. $# gives the count of arguments.

How do you take user input in Bash?

Using the read command:

  read -p "Enter your name: " name
  echo "Hello, $name"

What is the difference between $@ and $*?
- Both represent all script arguments, but $@ treats them as separate strings, while $* treats them as a single string.
How do you define and use variables in Bash?
- Assign: name="P"
- Access: echo $name
- Variables are case-sensitive.
What is a here document (HEREDOC)?
- A way to pass multi-line input to a command:
```
  cat <<EOF
  This is a multi-line
  string in a script.
  EOF
```

How do you check if a file exists in Bash?

Using -e flag:

  if [ -e file.txt ]; then
      echo "File exists"
  else
      echo "File does not exist"
  fi

Linux Interview Questions: Set 1