How to perform grep operation on all files in a directory?

grep, linux, shell, subdirectory

Solution

In Linux, I normally use this command to recursively `grep` for a particular text within a directory:

grep -rni "string" *

where

- `r` = recursive i.e, search subdirectories within the current directory

- `n` = to print the line numbers to `stdout`

- `i` = case insensitive search

Problem

Working with xenserver, and I want to perform a command on each file that is in a directory, `grep`ping some stuff out of the output of the command and appending it in a file. I'm clear on the command I want to use and how to `grep` out string(s) as needed. But what I'm not clear on is how do I have it perform this command on each file, going to the next, until no more files are found.

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