$ snmpwalk -Of -v2c -c rpitesting localhost NET-SNMP-AGENT-MIB::nsExtensions
.iso.org.dod.internet.private.enterprises.netSNmp.netSnmpObjects.nsExtensions.2.1.0 = INTEGER: 1
.iso.org.dod.internet.private.enterprises.netSNmp.netSnmpObjects.nsExtensions.2.2.1.2.7.114.112.105.116.101.109.112 = STRING: "/bin/cat"
.iso.org.dod.internet.private.enterprises.netSNmp.netSnmpObjects.nsExtensions.2.2.1.3.7.114.112.105.116.101.109.112 = STRING: "/sys/class/thermal/thermal_zone0/temp"
[...]