Recursive text search with grep and file patterns

Question

Given this example folder structure:

/folder1/file1.txt
/folder1/file2.djd
/folder2/file3.txt
/folder2/file2.fha

How do I do a recursive text search on all *.txt files with grep from "/"?

("grep -r <pattern> *.txt" fails when run from "/", since there are no .txt files in that folder.)

Answer 1

My version of GNU Grep has a switch for this:

grep -R foo --include '*.txt' *

"--include=GLOB Search only files whose base name matches GLOB (using wildcard matching as described under --exclude)."

Answer 2

If you have a large number of files it would be useful to incorporate xargs into the command to avoid an 'Argument list too long' error.

find . -name '*.txt' -print | xargs grep <pattern>

Answer 3

find . -name '*.txt' -type f -exec grep <pattern> {} \;

Answer 4

Mannis answer would fork a new grep-process for every textfile. If you have lots of textfiles there, you might consider grepping every file first and pick the .txt-files when thats done:

grep -r <pattern> * | grep \.txt:

That's more disk-intensive, but might be faster anyway.

Answer 5

You may want to take a look at ack at http://betterthangrep.com, which has facilities for selecting files to search by filetype.