How to use `yes` with `xargs -p`?

Question

Let's say I have ls | xargs -n1 -p rm, how do I use yes or yes n to automatically answer the questions generated by the -p flag?

I tried yes n | (ls | xargs -n1 -p rm) but didn't work.

UPDATE: The question is not really about rm, it's about how to use yes properly. I have an alias or a function that uses xargs -p and I like the fact that it asks me and shows me what it's doing before doing it. When I know what it will do, I would like to be able to use yes to automatically go through all of the xargs -p in the function. So even though the example uses rm, it's not really about it.

Also just to be extra clear, I don't want to modify my alias or function to use or not use -p. I rather just input yes externally.

Tbh I thought that something like yes | some_function_asking_me_questions or some_function_asking_me_questions <( yes ) would have worked, but it didn't.

2nd EDIT: Another example: I have an alias to list AWS SNS topics in a region like:

alias delete_snstopics="list_sns | cut -f 2 | xargs -n1 -p aws sns delete-topic --topic-arn "

Then I have a function that for each region in AWS finds and prompts for deletion for those SNS topics. I want to see the aws sns delete-topic --topic-arn $1 that the xargs would run, because the id of the SNS topic is different every time and if something goes wrong I can match up the SNS id in the web console. Moreover at times I might not want to delete the SNS topic in a particular region. And that's why I want to use yes with this function, so that I can use the same function for partial deletion and full deletion, and still get useful output. Makes sense?

Answer 1

Let's analyse your command:

yes n | (ls | xargs -n1 -p rm)

The pipeline ls | xargs -n1 -p rm has ls reading standard input, but having standard output redirected to xargs, which takes it as standard input, and has its standard output unaltered.

Now you pipe the output of yes into this pipeline. Since the standard input of that pipeline goes into ls, which doesn't even read it, xargs cannot see any of it.

Now the obvious question is: How can xargs ask you whether to execute the command? After all, its standard input (where programs normally would read user interaction) is redirected to read the output of ls!

Well, the answer is that xargs bypasses the redirection mechanism for those questions by just opening the terminal file /dev/tty directly. Therefore the confirmation input is unaffected by file redirection.

To input to xargs, you need a program that can present the process with a terminal device controlled by the program. A very powerful (but also quite complicated) such program is expect. Unfortunately I don't know a simpler way to achieve what you want.

Answer 2

You can use:

ls | xargs -n1 rm -r

And this will work for directories or/and files.