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Environment Variables: $LSB_* → $SLURM_*

LSF and SLURM both set environment variables inside running jobs. You'll need to update any scripts that reference $LSB_* variables.

Variable mapping table

Purpose LSF SLURM
Job ID $LSB_JOBID $SLURM_JOB_ID (or $SLURM_JOBID)
Job name $LSB_JOBNAME $SLURM_JOB_NAME
Queue / Partition $LSB_QUEUE $SLURM_JOB_PARTITION
Submit directory $LSB_SUBCWD $SLURM_SUBMIT_DIR
Hostname list $LSB_HOSTS $SLURM_JOB_NODELIST
Number of processors $LSB_DJOB_NUMPROC $SLURM_NTASKS
Array job index $LSB_JOBINDEX $SLURM_ARRAY_TASK_ID
Array job ID (parent) $LSB_JOBID $SLURM_ARRAY_JOB_ID
Max array index $LSB_JOBINDEX_END $SLURM_ARRAY_TASK_MAX
Allocated GPUs $LSB_GPU_ALLOC $SLURM_GPUS_ON_NODE
Temporary directory $LSB_TMPDIR or $TMPDIR $TMPDIR

SLURM-only variables worth knowing

These variables don't have direct LSF equivalents but are useful in SLURM scripts:

Variable Description
$SLURM_CPUS_PER_TASK Number of CPUs allocated per task (set by --cpus-per-task)
$SLURM_MEM_PER_NODE Memory allocated per node in MB
$SLURM_ARRAY_TASK_MIN First index in the array
$SLURM_ARRAY_TASK_STEP Step size between array indices
$SLURM_ARRAY_TASK_COUNT Total number of tasks in the array
$SLURM_JOB_NUM_NODES Number of nodes allocated
$SLURM_NODELIST List of nodes allocated (compact format)
$SLURM_GPUS Total number of GPUs allocated

Example: updating a script

#!/bin/bash
#BSUB -J myjob
#BSUB -o logs/%J.out

echo "Job $LSB_JOBID running on $LSB_HOSTS"
echo "Working from $LSB_SUBCWD"
echo "Using $LSB_DJOB_NUMPROC processors"

cd $LSB_SUBCWD
./my_program --threads $LSB_DJOB_NUMPROC

#!/bin/bash
#SBATCH --job-name=myjob
#SBATCH --output=logs/%j.out

echo "Job $SLURM_JOB_ID running on $SLURM_JOB_NODELIST"
echo "Working from $SLURM_SUBMIT_DIR"
echo "Using $SLURM_NTASKS processors"

cd $SLURM_SUBMIT_DIR
./my_program --threads $SLURM_NTASKS

Search and replace

A quick way to catch variable references is to search your scripts for LSB_:

grep -rn 'LSB_' *.sh

The converter script handles the most common variable substitutions automatically.