Equivalent command to grep binary files

The command strings will extract all ascii data from a file, if you then grep its output, you can search for your data:

strings <filename> | grep "search text"

With GNU grep, you can use -a option to make it treats binary files as text files:

grep -ali -- string file

If your grep version does not support -a, you can use ack instead. With ack 1.x, you need to include -a option, with ack 2.x, you don't, since when searching include non-text file by default (only ignored non-text file when you did not specify any files).

Your question is about find binary files that contain a pattern (and we have already very good answers!). Complementary we may like to get the occurrences.

I often use

grep -aPo '.{0,20}pattern.{0,20}'  binfile

to get a surrounding context of 20-char.