/usr/bin/bash: No such file or directory

I have faced this following error while i am trying to run a software :

/afs/cern.ch/work/a/atnourji/ROOTAnalysisTutorial/build/atlas_build_run.sh: line 16: /usr/bin/bash: No such file or directory

Any advise for this matter are very appreciated ?

$ nano /afs/cern.ch/work/a/atnourji/ROOTAnalysisTutorial/build/atlas_build_run.sh :

#!/user/bin/bash

# Transmit errors: set -e

# Set up the environment: source /afs/cern.ch/work/a/atnourji/ROOTAnalysisTutorial/build/x86_64-centos7-gcc62-opt/setup.sh || exit 1

# Run the command: exec $* || exit 1 ~