HCC Summer Workshop 2023

Holland Computing Center

Holland Computing Center (HCC) is located at University of Nebraska-Lincoln. It provides computing resources to the affiliates of University of Nebraska system. Currently, the most advanced cluster that HCC has is swan. HCC provides High Performance Computing to its researchers.

June Summer Workshop

Every year HCC hosts a workshop in the summer teaching about the basics of High Performance Computing (HPC). It is usually in June. This year I got the opportunity to teach at the workshop. The lesson started with an introduction to Unix Shell. The shell is a program where users can type commands. With the shell, it’s possible to invoke complicated programs. The most popular Unix shell is the Bash. Bash is a program that lets the user run different commands from a command line interface (CLI). In case of the computing world, most of the clusters are designed to interact from a CLI. Learning Bash or shell commands is very helpful for researchers as it provides users with the tools to do a lot of pre and post processing directly from the terminal environment.

Bash

Software carpentry has a great lesson for the Unix Shell. The workshop followed the software carpentry’s lesson plan. The whole lesson is built in a way that makes it easier for anyone to start from scratch. Whenever I teach Bash I like to start by providing a background and usefulness for Bash. When I started using HPC for the first time at UNL, I had zero experience of using unix shell or terminal. I started to learn some of the very basic commands. I relied heavily on WinSCP for editing job submit file, looking through output and error messages, finding empty folders or jobs that failed. When I switched to a mac that pushed me to get better in using Bash. Mac did not have a good substitute of WinSCP. Cyberduck comes close but is still very far away from the functionalities that WinSCP offer.

I shared all these experiences with the students. I hope my experience and different use cases of Bash commands in my research will motivate the students.

Useful Tips and Tricks for Bash

Below are some of the commands and tips that I have found very useful for my work.

• Ctrl + A moves the cursor to the front of the line in the terminal.
• ls -lthr lets me easily find the last edited file in a directory.
• chmod +x or chmod 755 to make a file executable
• execute the script from terminal using a ./<script_file_name>
• $@ enables a shell script to accept any number of arguments