how perform grep operation on all files in a directory

Question

Working with xenserver, and I want to perform a command on each file that is in a directory, grepping some stuff out of the output of the command and appending it in a file.

Answer 1

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

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