Use xmllint $SCTDAQ_ROD_CONFIGURATION_PATH --xinclude --shell

	\" \" needed for long numbers
Find the MUR which contains module 13
     //module[sn=\"000000000000013\"]/ancestor::MUR 

Find the Rod which contains module 13
     //module[sn=\"000000000000013\"]/ancestor::rod

Find module 13
     //module[sn=\"000000000000013\"]

Get the modules in MUR 3
     //MUR[@id=3]/module

Find the serial number of module 4 in rod 0
     /configuration/partition/crate/rod[@id=0]//MUR/module[@id=4]//sn/text()

Count the number of oks-objects in a file 
     count(/oks-data/obj)

Is the serial number of module 4 in rod 0 = 20220170100001 (returns bool)
     /configuration/partition/crate/rod[@id=0]//MUR/module[@id=4]//sn/text()=20220170100001
