This is an old revision of the document!
Software
A common task that every user encounters at least once in his or her use of HPC systems is installing software. Whether that equates to running an install script or configuring/compiling/installing from source code, understanding the Linux environment; where software components belong within the filesystem; and knowing when and how to isolate individual software titles in their own space is critical to success.
The Linux environment
Inherited from Unix is the basic layout of the Linux filesystem: a hierarchy of containers called directories descend from the root directory which is simply named /. Each directory can contain files or varying types as well as directories (thus, the hierarchical nature of the filesystem).
There are some directory names of higher significance in Unix and Linux:
| Directory name | Purpose |
|---|---|
bin | Contains executables — programs (compiled or scripted) that the user can run (execute) |
etc | Contains configuration files that influence how programs execute |
include | Contains C/C++ header files associated with libraries that are present |
lib | Contains libraries — compiled subroutine/function bundles — that are used by executables |
lib64 | A variant of lib containing code that was compiled for 64-bit execution |
libexec | Contains executables the user is not meant to run directly, but will be executed by some other program or library |
share | Contains support files that an executable or library may use: help and documentation pages, data tables, etc. |
sbin | Contains executables that are meant to be run by someone with higher privileges (e.g. the root user) |
Most of the directories named above can be found in the root directory — /bin, /lib64, and /etc, for example — as well as in other parent directories. The /usr directory contains /usr/bin and /usr/lib64 (amongst others). The /usr/local directory contains /usr/local/bin and /usr/local/lib64, meant to hold components that are not integral to the operating system itself.