Is Hyper Threading enabled?

Needed a quick way to check if Hyper Threading was enabled on some RHEL boxes, ended up writing a quick "script" that can be copied onto the command line.

I'll go through it line by line just for fun:

First we grab all lines matching "core id" from /proc/cpuinfo, sort them (in case the id's where not listed in numeric order), list the unique values and count them

cores=`grep "core id" /proc/cpuinfo|sort|uniq|wc -l`

Using grep I count the number of lines matching "processor" from /proc/cpuinfo

procs=`grep -c "processor" /proc/cpuinfo`

If we fine less cores the processors then Hyper Threading must be on

if [[ "$cores" -lt "$procs" ]]; then
echo -e "\n$HOSTNAME: cores=$cores, processors=$procs\n    HyperThreading: Enabled"

If we find the same number of processors and cores the Hyper Threading is off

elif [[ "$cores" -eq "$procs" ]]; then
echo -e "\n$HOSTNAME: cores=$cores, processors=$procs\n    HyperThreading: Disabled"

If neither case matches then we have run into a failure, or our math doesn't work on this particular box

else
echo "epic failure"
fi

And the whole thing...

cores=`grep "core id" /proc/cpuinfo|sort|uniq|wc -l`
procs=`grep -c "processor" /proc/cpuinfo`
if [[ "$cores" -lt "$procs" ]]; then
echo -e "\n$HOSTNAME: cores=$cores, processors=$procs\n    HyperThreading: Enabled"
elif [[ "$cores" -eq "$procs" ]]; then
echo -e "\n$HOSTNAME: cores=$cores, processors=$procs\n    HyperThreading: Disabled"
else
echo "epic failure"
fi