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Some of my directories have, mostly, subdirectories in them. When I run a utility that I aim at all files, for instance: , error reports on the directories swamp target output. I usually redirect error output to /dev/null, though using -d skip would be better, but I never want to be told that my file-aimed utility doesn't work on a directory, would rather have it do that silently. Most utilities lack grep's -d switch, for which the default action should be skip.

"Why don't file-aimed utilities skip directories unless told to recurse?" 'cos thats the way the developer wrote it!

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* is evaluated by the shell before even the grep command has been started.
At the end all the content of * (files, dirs, links, whatever) will be passed to the command.
grep can only state that those arguments are not "greppable" at all.
So if you don't want to use grep on a dir don't pass it to grep, don't use *.

Otherwise you can use set -x to see what's going on.

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They've all changed over time.

grep has a -d switch; read is the default; skip could be. There could be an environment variable GREP, analogous to LESS, to set default switches.

This is easier said than done. It can be hard to pass an argument that applies to all files and no directories.

If you cared to read the man page, you'd find out that there is such a variable.

again, it is made by the shell. grep will get those dirs, one by one, as an argument. What do you think what should grep do with them?
Dirs are skipped, exactly as you explained. The only thing is grep will report it. And may set the exit code.
and there is a way to do that. You can define an alias to add your flags, or use GREP_OPTIONS, if available

Well, if it is really needed....

I read the man page before I started this thread. I saw that there's GREP_COLORS to specify colors used in the display, but no others. What's so special about colors?

What I want.

They aren't treated as they would be if one used the -d skip switch, which seems to be the definition of skipping.

Then I have to remember to use the alias and it won't work on other computers.

It doesn't work, and the page to which you refer is old and says it will be removed. It used to exist, now doesn't. The decision behind that is the answer to my question.

That's not the standard. There's lots of stuff that's convenient but unnecessary. Lots of other utilities read environment variables; grep reads GREP_COLORS.

What other utils annoy you by not recursing?


BonusTurd: ack with globstar: https://stackoverflow.com/questions/...formance-issue


Question for LQgurus: "By default, ACTION is read, i.e., read directories just as if they were ordinary files"
doesn't seem true! It refuses & says: ... Is a directory

The shell glob examines the directory contents and does not further examine the file types.
You can use find
Switch your shell to zsh? In zsh you can do

glob * is handy for global files copy, move and such
For doing stuff more specific, it could be better to use *.extension (if files have extensions)
You can even use multiple extensions matches like *.{pdf,PDF,jpg,JPG}

unfortunately it is not the way how programs work. They never know what you (or me) wanted, but they do what was implemented.
The program which will do exactly what I want does not exist (at this moment).

You still don't understand, grep will not get the *, will not evaluate/expand it by itself and therefore cannot select only files.
It is the shell which will do the command line evaluation, before execution, and * will be replaced to the list of items in the current directory. Including everything (what is inside). And the shell does not care the arguments passed to grep (like -d).
So grep will get that list (of everything) and will try to use them one by one. In case of a file the search will be executed, in case of non-file arguments it will be reported: XXX is a directory (and the pattern won't be searched in a dir, it would have a different meaning).

___ explained (post #8), --directories=skip will tell grep to skip dirs silently do not print that message.
Additionally you may try --exclude-dir=* too (just need to use correct quotations).

Yes if you need this you need to create an alias containing your additional option(s), use a grep which can handle GREP_OPTIONS, or create a function to do that. And yes, you need to do that on all of your hosts.

grep used to work this way. I asked why it doesn't any longer.

I always understood. grep used to read an environment variable that one could set. I asked why it doesn't any longer.

I think it was never working that way. That's why it doesn't do it "any longer".

GREP_OPTIONS was intentionally removed, and that is also explained on the linked page.

How can it never have worked that way and also be intentionally removed?

I just rewrote grep's source to make it skip directories by default. It works. If I can do it, they can. Notice I don't say that they should. I asked why they don't even have an environment variable to read to make it work that way.

those are two different and independent things.
1. grep reports dirs
2. the removal of that variable

this may work now for you, but not for everybody and everywhere.