How do you grep results from 'find'?

Question

Trying to find a word/pattern contained within the resulting file names of the find command.

For instance, I have this command:

find . -name Gruntfile

Answer 1

Use the -exec {} + option to pass the list of filenames that are found as arguments to grep:

find -name Gruntfile.js -exec grep -nw 'purifycss' {} +

This is the safest and most efficient approach, as it doesn't break when the path to the file isn't "well-behaved" (e.g. contains a space). Like an approach using xargs, it also minimises the number of calls to grep by passing multiple filenames at once.

I have removed the -e and -r switches, as I don't think that they're useful to you here.

---

An excerpt from man find:

-exec command {} +
This variant of the -exec action runs the specified command on the selected files, but the command line is built by appending each selected file name at the end; the total number of invocations of the command will be much less than the number of matched files.

Answer 2

When too many files exist for the * expansion to run:

$ grep -o 'xxmaj\|xxbos\|xxfld' train/* | wc -l
-bash: /bin/grep: Argument list too long
0

Then this code fixes the “too long” problem:

$ find junk -maxdepth 1 -type f | xargs grep -o 'TVDetails\|xxmaj\|xxbos\|xxfld' 
junk/gum-.doc.out:TVDetails
junk/Zv0n.doc.out:TVDetails
$ find junk -maxdepth 1 -type f | xargs grep -o 'TVDetails\|xxmaj\|xxbos\|xxfld' | wc -l
2

It runs faster on my system, and maybe yours, when using the -P 0 option:

$ /usr/bin/time -f "%E Elapsed Real Time" find train -maxdepth 1 -type f | xargs -P 0 grep -o 'TVDetails\|xxmaj\|xxbos\|xxfld' | wc -l
0:02.45 Elapsed Real Time
358
$ /usr/bin/time -f "%E Elapsed Real Time" find train -maxdepth 1 -type f | xargs grep -o 'TVDetails\|xxmaj\|xxbos\|xxfld' | wc -l
0:11.96 Elapsed Real Time
358

Hope this helps.

Answer 3

While this doesn't strictly answer your question, provided you have globstar turned on (shopt -s globstar), you could filter the results in bash like this:

grep something **/Gruntfile.js

I was using religiously the approach used by Tom Fenech until I switched to zsh, which handles such things much better. Now all I do is:

grep text **/*(.)

which greps text through all regular files in current directory.

I believe this to be much cleaner syntax especially for day-to-day work in shell.