Sounds like a good time to mention that "Little Brother" by Cory Doctorow is available in GNU Info format (usually used for manpages).
Linux
It's going to be different for different file formats. For example, something like epub is going to be hard because the format is really just a zip file with a specific internal file structure. So, it's not really the .epub file you want to grep, but one of the files within that zip file you want to grep through. EBooks stored as PDFs could be a bit easier, as they are a monolithic file format with text often (though not always) stored just as plain text. However, the text streams can be encrypted and/or compressed (FlateDecode); so, there is no guarantee of seeing plain text.
I'm sure there are more formats, but I think you get the idea, how you would do a string search comes down to the actual file format. And some are not going to be easily greppable. It's not impossible, just not straight forward.
ls
lists files, if you pipe it to grep it will print matching lines with file names. Universally you can't grep through ebook content, but you can do it with epub, probably other zipped text formats using zipgrep
or just unzipthem and grep unarchived files.
Thanks!
Yeah, that's to be expected with ls as it only lists the folder contents. Which format do you have?
epub, mobi and pdf
grep searchTerm file
You can't grep zip archives directly.
Ripgrep-all has that capability.
Good to know.