Control Statement

  • let run multiple commands or conditionally execute commands.
  • Commonly used in scripts, but also on the command line.

1. Semicolon

  • Run multiple commands sequentially, regardless of success. Format: command1; command2; command3

Example : 

echo "Hello Alamgir"; ls /fakefolder; echo "Done"
# Hello Alamgir
# ls: cannot access '/fakefolder': No such file or directory
# Done

2. Double Ampersand

  • a logical AND operation
  • Run the second command only if the first succeeds.
  • Format : command1 && command2 Example: 
    echo "Hello Alamgir" && ls /fakefolder && echo "Done"
# Hello Alamgir
# ls: cannot access '/fakefolder': No such file or directory

3. Double Pipe

  • a logical OR operation
  • Run the second command only if the first fails ,skips it if the first succeeds.
  • Format : command1 || command2 Example:
echo "Hello Alamgir" || ls /fakefolder || echo "Done"
# Hello Alamgir

ls /fakefolder || echo "Hello Alamgir" || echo "Done" || echo "4th Command"
# ls: cannot access '/fakefolder': No such file or directory
# Hello Alamgir