grep -Fx ABB.log a.tmp
From the grep man page:
-F, --fixed-strings Interpret PATTERN as a (list of) fixed strings-x, --line-regexp Select only those matches that exactly match the whole line.
Simply specify the regexp anchors.
grep '^ABB\.log$' a.tmp
Here is what I do, though using anchors is the best way:
grep -w "ABB.log " a.tmp