Grep using list of words from a file.
You need to use the option -f : $ grep -f A B The option -F does a fixed string search where as -f is for specifying a file of patterns. You may want both if the file only contains fixed strings and not regexps. $ grep -Ff A B You may also want the -w option for matching whole words only: $ grep -wFf A B Read man grep for a description of all the possible arguments and what they do. NOTE: A= file. Searching in file B to see if ANY of the words in file A occur in it.