IDL is a data analysis programming language. Only authorised users can use IDL.

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Getting started

In order to use IDL on the ARC clusters, you will need to contact your department for licence server information. This will normally be provided as a port and a machine name in the format:


You will need to set the LM_LICENSE_FILE environment variable before you use IDL:

export LM_LICENSE_FILE=port@machine:$LM_LICENSE_FILE

After that, you should be able to load the IDL module:

module load idl

and then run the application by entering the command idl

Running IDL as a batch job

A suitable script to run an IDL program as a batch job with no interaction is:

#$ -V -cwd
#$ -l h_rt=6:00:00
#$ -l h_vmem=1G

module load idl

This will run the application:

  • from your current directory with the currently loaded module environment
  • with 6 hours of run-time
  • requesting 1GByte of memory

If this is saved as a text file with the name: it can then be submitted with:


Running IDL as an interactive job on the compute nodes

IDL can also be launched as an interactive job on the back-end compute nodes through qrsh :

export LM_LICENSE_FILE=port@machine:$LM_LICENSE_FILE
module load idl
qrsh -cwd -V -l h_rt=6:00:00,h_vmem=1G -pty y $IDL_HOME/idl/bin/idl

This will request 1 cpu for 6 hours, with 1G of RAM.

Not that if the resources are not available at the point the scheduler tries to allocate them, then the request will fail.

You may find you have to submit the request a few times until it is successful.