Check if file contains some text (not regex) in Unix

Question

I want to check if a multiline text matches an input. grep comes close, but I couldn't find a way to make it interpret pattern as plain text, not regex.

How can I do this, using only Unix utilities?

Answer 1

Use grep -F:

-F, --fixed-strings

Interpret PATTERN as a list of fixed strings, separated by newlines, any of which is to be matched. (-F is specified by POSIX.)

EDIT: Initially I didn't understand the question well enough. If the pattern itself contains newlines, use -z option:

   -z, --null-data
          Treat  the  input  as  a set of lines, each terminated by a zero
          byte (the ASCII NUL character) instead of a newline.   Like  the
          -Z  or --null option, this option can be used with commands like
          sort -z to process arbitrary file names.

I've tested it, multiline patterns worked.

Answer 2

From man grep

-F, --fixed-strings
       Interpret  PATTERN  as  a  list  of  fixed strings, separated by
       newlines, any of which is to be matched.  (-F  is  specified  by
       POSIX.)