Then there's grep -whor which is also super useful.

Thanks! I didn't knew about -o.

My most common grep phrase is grep -iIRn - good for searching in code (when IDE can't find something). You can remove -i if you care about case, but I mostly used it for plsql code, and that's not case-sensitive.

What does that do?

Pinches whole-words (by regex usually, e.g. '[A-Z][A-Za-z]*Exception') out of files recursively. Then throw in sort and uniq -c.

example? I tried a few things, clearly since -r it's not a single file grep, but throwing in -h with -r is confusing. I thought I was pretty good at grepping...

-r everyone needs, but usually -R is a better default since it does not ignore symlinks

-h I practically never use since I'm almost always using grep to find what file I need to further investigate and letting the stuff down the | line deal with it

-o makes sense, kinda, I want to do that in the next stage of the pipe, maybe I have used it once? cant remember

but -w... I feel like I'm missing something there.

I think you have dramatically different usage patterns than me. I use -o all the time. I only know -w for a limited time, but it's one of my favorite options since you can filter out a lot of garbage. You could replace it with grep -P '\bpattern\b', I guess.

I think what you are doing here is search, but -o and -w shine at data extraction and data manipulation. Things you would use Excel for, except on multiple GB files.

Very interesting. I'm still floundering for a use case... can you give an outline if it's difficult to make a specific example?

If you are not using search, but are using a recursive (-r) grep, then you are feeding a bunch of data to your pipe but don't care what file it came from. I get that... I mirrored the SEC's ftp back when it was ftp... and it's interesting for correlation and name stuff... but that's not going to work because it's freeform, and it's millions of small files... so you are using (large) files with a known format? Something like spectral datasets where the fields are passed with the data prefixed with it's important tags? Maybe logs?

As I have already said,

    grep -whor '[A-Z][A-Za-z]*Exception' * | sort | uniq -c

for a histogram of exceptions inside logs downloaded from a bunch of nodes.

As for -w, my favourite case is https://unix.stackexchange.com/questions/110645/select-lines...

As for -o,

    grep -o ........-....-....-....-............

It may look like Morse code, but what it does is greps UUIDs out.

Ahhh. TIL!

cool stuff, i was messing around with this. To then take that list of exceptions and find them back the actual files again, tack on at the end: `| grep -Fwf - *`