linux_course_doc/modules/qualifying/exercises_bashscripting.md

Bash scripting exercises

Write a script that outputs interesting network information

The script takes no arguments and just outputs interesting information about the network in an easy to read format. Output at the minimul the following information but more is better.

• internal ip address
• external ip address
• default route
• the nameservers used by the machine
• your hostname

Additional challenges

• see if you can ping 8.8.8.8 and display only the time it takes
  • can you ping the same host multiple times and calculate the average?
  • display an error message if the destination can not be reached
• evaluate the quality of the uplink with speedtest-cli and echo back some relevant information (but not all)

Write an alarm clock

TODO (IPC exercise)

Automate adding users to your machine

Write a script that can add a list of users to your system. Make it so that the newly created users have a default password that is the same as their username. You can go about this in two ways, either the command line arguments are the usernames, or the first command line argument supplies a text file where every line is a user.

./my_script.sh bob alice marie camille roger
./my_script.sh /path/to/user/list.txt

In the second example the /path/to/user/list.txt file would contain the following lines.

bob
alice 
marie 
camille 
roger

Additional challenges

• display an error message when the script is executed as a non root user
• add all of the new users to a specific group
• put all of the new users $HOME directory in a distinct folder so that their home would be /home/students/$HOME
• write a second script that removes these users from the system and also removes all traces of their existance
• how could you combine both scripts into one big script?
• how would you force the new users to change their password upon first login? (might require an additional script)