Why does this Bash NRPE plugin not return a variable to Nagios?

This script I have here works locally just fine: #! /bin/bash volts=sudo vcgencmd measure_volts core|sed 's/volt=\([0-9\.]*\)V/\1/' echo -n "BCM2835 SoC Voltage is ${volts}V " echo "| volts=$volts;1.5;1.5;0;1.5" However if Nagios tries to get the information it only gets "BCM2835 SoC Voltage is V" as if the variable was not defined. There are also other plugins which pull the information from files and it works. So I managend to write the information in a temp file and write it back into the variable. #! /bin/bash sudo vcgencmd measure_volts core|sed 's/volt=\([0-9\.]*\)V/\1/'>/tmp/volts volts=$(