bash - How to use grep to find string that contain "\n" char? -

i want use powerful grep find strings contain following sentence in matlab source files in directory.

    fprintf('error: invalid indexes!\n');

i've tried following command, shows errors.

    grep -rl "fprintf(\'error: invalid indexes!\\n\');" ./

i've tried solutions presented in here, seems not work.

could please give advice?

in addition, after find matched strings, want replace them following sentence:

    if(length(invalid_idx)>0) fprintf('error: invalid indexes!\n'); end

i know use following command:

    grep -rl "need_to_replaced_strings" ./ | xargs sed -i 's/need_to_replaced_strings/replaced_strings/g'

i'm not sure if replaced_strings in command above should have special considerations.

the errors follows: enter image description here

try this:

$ grep -erl 'fprintf\('\''error: invalid indexes!\\n'\''\);' ./  fprintf('error: invalid indexes!\n');

use -e option , escape inner single quotes'\'' outside single-quoted string.

or, if escape single quotes '"'"' below:

$ grep -erl 'fprintf\('"'"'error: invalid indexes!\\n'"'"'\);' ./

Deter