Grep Recursively Through Single File Extension

You can use the following grep command to search through a directory, recursively, but only looking at a specific file pattern.

grep -r --include=<pattern> <string> <directory>

Here is an example that searches recursively starting at /home/joel/ and including only php files.

grep -r --include=*.php "public auction" ./

Other options you might want to add to the command:

Here's another example with the -r, -i and -o options all added.

grep -rio --include=*.php "public auction" ./