Currently, the shell script generated by the Pegasus Shell Code Generator has the following snippet in the starting that needs to be updated

#!/bin/bash
#

1. executes the workflow in shell mode
   #

if [ "X${PEGASUS_HOME}" = "X" ]; then
echo "ERROR: Set your PEGASUS_HOME variable" 1>&2
exit 1
fi

if [ ! -e ${PEGASUS_HOME}/libexec/shell-runner-functions.sh ];then
echo "Unable to find shell-runner-functions.sh file."
echo "You need to use Pegasus Version 3.0 or higher"
exit 1
fi
. ${PEGASUS_HOME}/libexec/shell-runner-functions.sh