grep, but only certain file extensions?

Question

I am working on writing some scripts to `grep` certain directories, but these directories contain all sorts of file types. I want to `grep` just `.h` and `.cpp` for now, but maybe a few others in the future. So far I have: { grep -r -i CP_Image ~/path1/; grep -r -i CP_Image ~/path2/; grep -r -i CP_Image ~/path3/; grep -r -i CP_Image ~/path4/; grep -r -i CP_Image ~/path5/;} | mailx -s GREP [email protected] Can anyone show me how I would now add just the specific file extensions?

Answer 1

easy answer

grep 'pattern' *.c *.h

a fancier answer for whole subtrees is

find directory -name *.c -exec grep -Hn 'pattern' {} \;

... and yes, you need the '\;' for find. You also want -Hn so that grep will tell you which files you found matches in.

a slightly more modern version is

find directory -name '*.c|*.h' | xargs grep -Hn 'pattern'

similar tools include the Silver Searcher ag but in general the answer is a program that will search all the files in a subtree and execute grep or something similar.

See man 1 find, man 1 grep, man 1 xargs.

Answer 2

Not sure if I'm seeing the full context of your question, but would using find like this work for you?

grep "...pattern..." $(find . -type f -name "*.h" )

grep "...pattern..." $(find . -type f -name "*.cpp" )

OR

grep "...pattern..." $(find /some/dir/path -type f -name "*.h" )

grep "...pattern..." $(find /some/dir/path -type f -name "*.cpp" )

Depending on how many files you're processing .... if find winds up generating a very long list (one that exceeds maximum command param memory), you might need to do something like this .... same affect.

find /some/dir/path -type f -name "*.h" exec grep "...pattern..." {} \;

Yes, the trailing \; is significant ... not to be explained here

Answer 3

# will search regexp "regexp" in header files.

grep regexp *.h