Grep multiple strings from text file

Question

Okay so I have a textfile containing multiple strings, example of this -

Hello123
Halo123
Gracias
Thank you
...

I want grep to use these strings to find lines with matching strings/keywords from other files within a directory

example of text files being grepped -

123-example-Halo123
321-example-Gracias-com-no
321-example-match

so in this instance the output should be

123-example-Halo123
321-example-Gracias-com-no

Answer 1

With GNU grep:

grep -f file1 file2

-f FILE: Obtain patterns from FILE, one per line.

Output:

123-example-Halo123
321-example-Gracias-com-no

Answer 2

You should probably look at the manpage for grep to get a better understanding of what options are supported by the grep utility. However, there a number of ways to achieve what you're trying to accomplish. Here's one approach:

grep -e "Hello123" -e "Halo123" -e "Gracias" -e "Thank you" list_of_files_to_search

However, since your search strings are already in a separate file, you would probably want to use this approach:

grep -f patternFile list_of_files_to_search