GREP:Output all lines containing word

Output all lines in the file temp that contain the word dog
using GREP only and in one line!!!

I tried grep '[[:space:]]dog[[:space:]]' temp

but it doesnt catch word dog when is at beginning or end, like:

Our dog is nice /this OK
Nice dog /this NOT
dog good /this NOT

Thank you!!!

Try...

egrep '(^|[[:space:]])dog($|[[:space:]])' temp

I would do:

grep ".*dog.*" temp

Oops, my way would make the following acceptable:

"a furious bulldog"

so Ygor's got it.