Under *nix, how can I find a string within a file within a directory?

Question

I'm using ubuntu linux, and I use bash from with a terminal emulator every day for many tasks.

I would like to know how to find a string or a substring within a file that is within a particular directory.

If I was knew the file which contained my target substring, I would just cat the file and pipe it through grep, thus:

cat file | grep mysubstring

But in this case, the pesky substring could be anywhere within a known directory.

How do I hunt down my substring ?

Answer 1

Use a shell wildcard:

grep mysubstring *

If you want to search subdirectories, use the -r option to recurse into them:

grep -r myssubstring .

Answer 2

find -type f | xargs grep mysubstring

These commands (find, xargs and grep) have lots of options, so you can tune this operation substantially.

Answer 3

say I want to find all the python code files that contain the text "wiki" under the directory "~/projects", here is the script:

grep -lir "wiki" ~/projects/**/*.py

adjust the script to your specific requirements.

Answer 4

If you don't need to do it in batch mode, you could install midnight commander (mc), it can search for strings in files.

Answer 5

No matter how you do it, don't cat files into grep. Your original version of

cat file | grep mysubstring

is more correctly done as

grep mysubstring file

Answer 6

If you want to find all files with a certain String recursive from "current" dir, use:

find . -type f -exec grep -l mysubstring {} \;

(should work on most *nix')