I want to find files containing two strings together, for example the file contains both
I want the full path of files in output. I don't want to see "permission denied" warnings.
which is the same as
Edit: heres why
Nothing found, but file b contains both strings.
Here's what I think alwbtc wants
To elaborate on @RedGrittyBrick's solution which has a shortcoming when running the command unattended plus to suppress error output as intended and to find files recursively you might consider
or less redundantly:
This will work if the strings are on different lines of the same file and will also avoid false positives if a filename contains one of the strings.