Perl is a scripting language with cross-platform standardization - scripts developed on one platform should run unchanged on another platform. It is heavily used in place of shell scripting, and is easily extensible, as evidenced by the large number of available modules on the Comprehensive Perl Archive Network.
Versions and Availability
Module Names for perl on qb
▶ Module FAQ?
The information here is applicable to LSU HPC and LONI systems.
A user may choose between using /bin/bash and /bin/tcsh. Details about each shell follows.
System resource file: /etc/profile
When one access the shell, the following user files are read in if they exist (in order):
- ~/.bash_profile (anything sent to STDOUT or STDERR will cause things like rsync to break)
- ~/.bashrc (interactive login only)
When a user logs out of an interactive session, the file ~/.bash_logout is executed if it exists.
The default value of the environmental variable, PATH, is set automatically using SoftEnv. See below for more information.
The file ~/.cshrc is used to customize the user's environment if his login shell is /bin/tcsh.
Modules is a utility which helps users manage the complex business of setting up their shell environment in the face of potentially conflicting application versions and libraries.
When a user logs in, the system looks for a file named .modules in their home directory. This file contains module commands to set up the initial shell environment.
Viewing Available Modules
$ module avail
displays a list of all the modules available. The list will look something like:
--- some stuff deleted --- velvet/1.2.10/INTEL-14.0.2 vmatch/2.2.2 ---------------- /usr/local/packages/Modules/modulefiles/admin ----------------- EasyBuild/1.11.1 GCC/4.9.0 INTEL-140-MPICH/3.1.1 EasyBuild/1.13.0 INTEL/14.0.2 INTEL-140-MVAPICH2/2.0 --- some stuff deleted ---
The module names take the form appname/version/compiler, providing the application name, the version, and information about how it was compiled (if needed).
Besides avail, there are other basic module commands to use for manipulating the environment. These include:
add/load mod1 mod2 ... modn . . . Add modules rm/unload mod1 mod2 ... modn . . Remove modules switch/swap mod . . . . . . . . . Switch or swap one module for another display/show . . . . . . . . . . List modules loaded in the environment avail . . . . . . . . . . . . . . List available module names whatis mod1 mod2 ... modn . . . . Describe listed modules
The -h option to module will list all available commands.
Module is currently available only on SuperMIC.
The command to run the interpreter is perl, and it can be used in interactive and scripted modes. The details of the language can be found in the Resources documents.
▶ Executable Scripts FAQ?
All shells and most interpreters (i.e. Python, Tcl, gawk, R, etc.) can be used to create executable scripts. This is accomplished through the magic of the shell #! line, which is a special comment line. The line, which must be the first line of the script, specifies the path to the program that can interpret the main contents of the file, which are command lines the language understands. Once the script is written, set it executable with chmod. A few examples should serve to illustrate the general idea.
Executable Bash Script
A simple script to echo out Hello World and do a long ls listing.
#!/bin/bash echo "Hello World!" ls -l
If the above is in a file named hello.sh, it can be made executable for the user (i.e. see man chmod for other possibilities) and run with:
$ chmod u+x hello.sh $ ./hello.sh
Here are some line usable with other scripting languages. In most cases, options allowed by the command used can be provided on the #! line. Note: that the paths should be verified and not use blindly. In particular command shells tend to reside in different directories.
gawk: #!/bin/gawk tcsh: #!/usr/bin/tcsh tcl: #!/usr/local/bin/tcl
Last modified: August 23 2017 10:59:58.