in reply to
How to grep exact string
What output are you expecting and what are you getting? I get the following with what you posted. Is it not what you wanted/intended?
Machines extra in second list
newly in this nt64osbld2
already there nt64osbld2tmp
newly in this nt64osbld3
newly in this nt64oscitrix1
newly in this ntosbld4
newly in this ntosbld5
newly in this ntosbld6
already there vm-nt64osbld2
already there vm-nt64osbld3
already there vm-nt64osbld4
already there vm-nt64osbld5
already there vm-nt64osremot1
already there vm-nt64osremot2
already there vm-nt64osremot3
already there vm-nt64osremot4
already there vm-nt64osremot5
already there vm-nt64osremot6
already there vm-nt64osremot7
already there vm-nt64osremot8
already there vm-ntosbld1
already there vm-ntosbld5
already there vm-ntoscert3
already there vm-ntosdev1
already there vm-os2k8r264-01
already there vm-osremote1
already there vm-osremote10
already there vm-osremote2
already there vm-osremote3
already there vm-osremote4
already there vm-osremote5
already there vm-osremote6
already there vm-osw2k8-1
already there vm-osw2k8-2
newly in this vm-osw2k8x64-1
newly in this vm-osw2k8x64-2
already there vm-oswin2k3-32
already there vm-oswin2k3-64
EDIT: After incorporating tobyink's or ColonelPanic's suggestion, I get the same results, but it is now safe against regex metacharacters