if [ "x$HAVE_CIFS" = "xyes" ]; then
if [ "$HAVE_CIFS" = "yes" ]; then
in above 2 methods method one is safest as it deals with versions of "test" that don't deal with empty strings correctly.
Now onwards i will try to use the safest way whenever is possible.
More of Robust scripting article can be found in following blog entry.