Just thought I would add a way to show the info for Boris's answer. As was just puzzled by time again. In bash type is your friend. I should really remember to use it more. Old csh habits die hard.

which -a time
/usr/bin/time

type time
time is a shell keyword

type times
times is a shell builtin

type nslookup
nslookup is /usr/bin/nslookup

Just thought I would add a way to show the info for Boris's answer.

As was just puzzled by time again.

In bash type is your friend. I should really remember to use it more. Old csh habits die hard.

which -a time  
/usr/bin/time

type time 
time is a shell keyword

type times  
times is a shell builtin

type nslookup  
nslookup is /usr/bin/nslookup