Transferring Files

Creating and Changing Folders

On a Windows or Mac desktop, our present location determines what files and folders we can access. I can “see” my present location visually with the help of the graphic interface - I could be looking at my Desktop, or the contents of a folder, for example. In a Linux command-line interface, we lack the same visual cues to tell us what our location is. Instead, we use a command - pwd (print working directory) - to tell us our present location. Try executing this command on Frontera:

[frontera]$ pwd
/home1/02555/lima

This home location on the Linux filesystem is unique for each user, and it is roughly analogous to C:\Users\username on Windows, or /Users/username on Mac.

To see what files and folders are available at this location, use the ls (list) command:

[frontera]$ ls

I have no files or folders in my home directory yet, so I do not get a response. We can create some folders using the mkdir (make directory) command. The words ‘folder’ and ‘directory’ are interchangeable:

[frontera]$ mkdir folder1
[frontera]$ mkdir folder2

[frontera]$ ls
folder1 folder2

Now we have some folders to work with. To “open” a folder, navigate into that folder using the cd (change directory) command. This process is analogous to double-clicking a folder on Windows or Mac:

[frontera]$ pwd
/home1/02555/lima
[frontera]$ cd folder1
[frontera]$ pwd
/home1/02555/lima/folder1

Use ls to list the contents. What do you expect to see?

[frontera]$ ls

There is nothing there because we have not made anything yet. Next, we will navigate back to the home directory. So far we have seen how to navigate “down” into folders, but how do we navigate back “up” to the parent folder? There are different ways to do it. For example, we could use a shortcut, .., which refers to the parent folder - one level higher than the current location:

[frontera]$ cd ..
[frontera]$ pwd
/home1/02555/lima

We are back in our home directory. Instead, we could specify the complete path of where we want to go, in this case cd /home1/02555/lima. Finally, let’s remove the directories we have made, using rm -r to remove our parent folder folder1 and its subfolders. The -r command line option recursively removes subfolders and files located “down” the parent directory. -r is required for folders.

[frontera]$ rm -r folder1
[frontera]$ ls
folder2

Transferring Files to and from Frontera

To practice transferring files to Frontera’s $WORK and $SCRATCH, we need to identify the path to our $WORK and $SCRATCH directory. To identify these paths, we can use helpful command shortcuts.

To identify the path to our $WORK directory, we can use cd $WORK or the helpful shortcut cdw:

[frontera]$ cdw
[frontera]$ pwd
/work2/02555/lima/frontera

To identify the path to our $SCRATCH directory, we can use cd $SCRATCH or the helpful shortcut cds:

[frontera]$ cds
[frontera]$ pwd
/scratch1/02555/lima/frontera

Copying files from your local computer to Frontera’s $WORK would require the scp command (Windows users use the program “WinSCP”):

[local]$ scp my_file lima@frontera.tacc.utexas.edu:/work2/02555/lima/frontera
(enter password)
(enter token)

In this command, you specify the name of the file you want to transfer (my_file), the username (lima), the hostname (frontera.tacc.utexas.edu), and the path you want to put the file (/work2/02555/lima/frontera). Take careful notice of the separators including spaces, the @ symbol, and the colon.

Copying files from your local computer to Frontera’s $SCRATCH using scp:

[local]$ scp my_file lima@frontera.tacc.utexas.edu:/scratch1/02555/lima/frontera
(enter password)
(enter token)

Copy files from Frontera to your local computer using the following:

[local]$ scp lima@frontera.tacc.utexas.edu:/work2/02555/lima/frontera/my_file ./
(enter password)
(enter token)

Note: If you wanted to copy my_file from $SCRATCH, the path you would specify after the colon would be /scratch1/02555/lima/frontera/my_file.

Instead of files, full directories can be copied using the “recursive” flag (scp -r ...).

This is just the basics of copying files. See example scp usage here.

Exercise

1. Download the file firststeps.zip.

2. Login to Frontera.

3. Identify your $WORK directory path using cdw and pwd.

4. From your local computer, copy the file firststeps.zip to Frontera. (You will need to know where the file firststeps.zip was downloaded on your local computer and navigate to this folder.)

5. Login to Frontera, navigate to your $WORK, and unzip the file using unzip firststeps.zip.

1. Download the file firststeps.zip.

2. Login to Frontera:

   [local]$ ssh username@frontera.tacc.utexas.edu
   (enter password)
   (enter 6-digit token)
   

3. Identify your $WORK directory path using cdw and pwd.

   [frontera]$ cdw
   [frontera]$ pwd
   /work2/02555/lima/frontera
   [frontera]$ logout
   

4. From your local computer, copy the file firststeps.zip to Frontera. (You will need to know where the file firststeps.zip was downloaded on your local computer and navigate to this folder.)

   [local]$ scp firststeps.zip lima@frontera.tacc.utexas.edu:/work2/02555/lima/frontera
   (enter password)
   (enter token)
   

5. Login to Frontera, navigate to your $WORK, and unzip the file using unzip firststeps.zip.

   [local]$ ssh username@frontera.tacc.utexas.edu
   (enter password)
   (enter 6-digit token)
   [frontera]$ cdw
   [frontera]$ unzip firststeps.zip
   

Review of Topics Covered

Command	Effect
pwd	print working directory
ls	list files and directories
mkdir dir_name	make a new directory
cd dir_name/	navigate into a directory
rm -r dir_name/	remove a directory and its contents
. or ./	refers to the present location
.. or ../	refers to the parent directory
cd $WORK, cdw	Navigate to $WORK file system
cd $SCRATCH, cds	Navigate to $SCRATCH file system
scp local remote	Copy a file from local to remote
scp remote local	Copy a file from remote to local