Find Files Without a Substring with Grep

After resolving a merge conflict in a large React codebase, the following error appeared:

Element type is invalid: expected a string (for built-in components) or a class/function

It seemed like one of the components was missing the export keyword. The question was just which component?

It's easy to find all files in a directory that do include a substring like export in the IDE and various terminal commands, but what about finding the files that don't include the export keyword?

Shell scripting to the rescue: After some research, I learned about some new CLI flags that could be used to solve this with the grep command, available in most Unix shells.

The following command recursively finds all files in the components directory (including its subdirectories) that don't include the export search string:

grep -riL "export" components

There's also an option to match files that do include a keyword, by replacing the -L flag with -l, as described here:

grep -ril "export" components

Quite a powerful way to quickly find what you need!