Environment

The Linux servers run the RedHat Enterprise Linux operating system.  All accounts are synchronized with instructional lab workstations, so if you can log into the instructional lab computers you can log into the Linux servers.

File Systems

Each user is assigned a permanent file area known as their home directory. On all of the machines users share the same home filesystem that is mounted from our central file server. In addition to your home areas, each system has a temporary area known as /tmp.

On the Linux servers, /tmp is not shared between nodes. /tmp represents space allocated on the local hard drive, which offers fast I/O space for running applications. Improvements in performance for serial codes can often be seen by running applications from /tmp and then copying data back to the home directory when the simulation is complete.

A few items to note about /tmp are:

  • The system removes files not accessed after 45 days
  • Files on /tmp are not backed-up by the system

Dot Files

A few basic skeleton files are provided to help you get started. These files are often referred to as dot files because they begin with a ".". Typically, they do not appear in a directory listing. To display a listing of these files, use the command

ls -a

.forward

File containing your local e-mail address. Note: the system and the center often rely on communications via e-mail. If your local e-mail address changes, please change the contents of the .forward file.

.profile

Start-up shell script for Korn, POSIX, and Bourne shell users. Users may modify this file to add/override any environment variables or conventions that were established by the system. For a list of current environment variables on a given system, enter the env command.

.login

Start-up shell script for C shell users. Users may modify this file to add/override any environment variables or conventions that were established by the system. For a list of current environment variables on a given system, enter the env command.

.bashrc

Start-up shell script for Bash shell, which is the default shell for all users. This is executed each time a new bash shell is invoked. Users may modify this file to establish variables and aliases.

TIP: Do not redefine your PATH environment variable without including ${PATH}. If you hard-code your PATH, it will break the modules software which allows users to access software packages, and as a result you may not be able to compile or submit batch jobs. The following is a better way to modify your PATH variable:

Korn shell (.profile)

PATH="${PATH}:${HOME}/bin" export PATH

C shell (.cshrc)

setenv PATH ${PATH}:${HOME}/bin

Compiling Systems

Both Intel and GNU compilers are provided.