How can I "grep" recursively filtering the name of the files I want with wildcards?

When I want to perform a recursive grep search in the current directory, I usually do:

grep -ir "string" . 

But that command searches inside all kinds of files, including binary files (pictures, audio, video, etc...) which results in a very slow search process.

If I do this, for example, it doesn't work:

grep -ir "string" *.php 

It doesn't work because there are no PHP files inside the current directory, but inside some of the subdirectories in the current directory, and the subdirectories' names don't end with ".php" so grep doesn't look inside them.

So, how can I do a recursive search from the current directory but also specifying filename wildcards? (i.e: only search in files which end in a specific extension)

3 Answers

Use grep's --include option:

grep -ir "string" --include="*.php" . 

If you have a version of grep that lacks the --include option, you can use the following. These were both tested on a directory structure like this:

$ tree . ├── a ├── b │   └── foo2.php ├── c │   └── d │   └── e │   └── f │   └── g │   └── h │   └── foo.php ├── foo1.php └── foo.php 

Where all the .php files contain the string string.

1. Use find

   $ find . -name '*php' -exec grep -H string {} + ./b/foo2.php:string ./foo1.php:string ./c/d/e/f/g/h/foo.php:string 

   Explanation

   This will find all .php files and then run grep -H string on each of them. With find's -exec option, {} is replaced by each of the files found. The -H tells grep to print the file name as well as the matched line.

2. Assuming you have a new enough version of bash, use globstar :

   $ shopt -s globstar $ grep -H string **/*php b/foo2.php:string c/d/e/f/g/h/foo.php:string foo1.php:string 

   Explanation

   As explained in the bash manual:

   globstar

   If set, the pattern ‘**’ used in a filename expansion context will match all files and zero or more directories and subdirectories. If the pattern is followed by a ‘/’, only directories and subdirectories match.

   So, by running shopt -s globstar you are activating the feature and Bash's globstar option which makes **/*php expand to all .php files in the current directory (** matches 0 or more directories, so **/*php matches ./foo.php as well) which are then grepped for string.

Use */*.php

This makes grep search one level of subdirectory