Linux basics

Linux basics#

A terminal is the standard way to interact with a supercomputer. It is worth learning the basics and getting comfortable with the “black box”, to make efficient use of the resources.

  • Login to the Roihu web interface, and start a login shell.

  • Check which directory you are in (type the command and hit Enter):

pwd

  • Check the contents of the directory:

ls -l

  • Change the to a another directory:

cd /scratch/project_2020458/students
pwd

  • Make a new directory with your username:

mkdir $USER
ls -l

  • Go to the new directory.

cd $USER

Auto complete

If you just type cd and the first letter of the folder name, then hit the tab key, the terminal completes the name. Handy!

  • Download a file into this new folder.

wget https://raw.githubusercontent.com/csc-training/csc-env-eff/master/part-1/prerequisites/my-first-file.txt
ls -l

  • Check the contents of the file:

less my-first-file.txt
# To exit the less, hit `q`.

  • Make a copy of this file:

cp my-first-file.txt $USER-second-file.txt    
ls -l
less $USER-second-file.txt

  • To move or rename a file:

mv $USER-second-file.txt $USER-third-file.txt
ls -l
less $USER-third-file.txt

  • Remove all files and folders created above

cd ..
rm -r $USER
ls -l

Re-executing commands from history

If you remember a part of a command that you have used recently you can search for it with the command history | grep string. This will show all your used commands that have included the string string (replace this with the pattern you are searching for).