Exercise: scripting in bash

Task

Part I

1. Download the example script using the following command, make it executable and run it.

    $ wget https://gist.githubusercontent.com/hurngchunlee/78ae286f079e4a68ed63/raw/check_login.sh
   

   Hint: use this wiki to understand the script.

2. Complete the ToDo parts in the script. The steps:
   • use the id command to check whether the user id given from the command argument is valid in the system (i.e. the user does actually exist), Hint: When the user does not exist in the system, the id command returns a non-zero number.
   • return a different number (2, for example) from the finduser function,
   • implement a corresponding option in the case switch to print out an error saying the user is not valid.

Part II

Download this file containing some accounting data concerning the number of completed computational jobs in the HPC cluster per user per day. Data are organised in four columns separated by a space character, from left to right, they are date, user id, number of completed matlab jobs and number of completed batch jobs.

• Write a script to calculate the overall cluster usage fraction of each user in terms of the number of completed jobs.
• Start from the following script template gimmick:gist

Solution

Part I

After completing the ToDo items in the check_login.sh script.

gimmick:gist

Part II

Usage percentage of the cluster per user, in terms of number of completed jobs.

gimmick:gist