External Tool: Numerically adding two values with 'bc'.

The workflow is an examples for the External Tools / UseCase plugin to integrate external tools. It wraps the "bc" command line calculator. Internally, it executes the following script:

if [ ! -r "$1" ]; then
        echo "Cannot read file indicated by first argument '$1'." ;
        exit -1 ;
fi ;
if [ ! -r "$2" ];then
        echo "Cannot read file indicated by second argument '$1'." ;
        exit -1 ;
fi

if [ -x /usr/bin/bc ]; then
        a=$(cat $1|tr -d '\n') ;
        b=$(cat $2|tr -d '\n') ;
        echo "$a+$b" | bc | tr -d '\n';
else
        echo "The bc tool is not installed where expected, if installed at all." ;
        exit -1 ;
fi

To develop workflows in a similar manner, i.e. avoiding the specification of beans and gain complete flexibility for local or remote execution of the workflow, please follow instructions on http://www.mygrid.org.uk/dev/wiki/display/developer/Calling+external+commands+from+Taverna.