How to grep thousands of files in a directory for hundreds of strings in a file

You can pass a directory as a target to grep with -R and a file of input patterns with -f:

  -f FILE, --file=FILE
          Obtain patterns from FILE, one per line.  If this option is used
          multiple  times  or  is  combined with the -e (--regexp) option,
          search for all patterns given.  The  empty  file  contains  zero
          patterns, and therefore matches nothing.

   -R, --dereference-recursive
          Read all files under each directory,  recursively.   Follow  all
          symbolic links, unlike -r.

So, you're looking for:

grep -Ff subset.txt -r objects/

You can get the list of matching files with:

grep -Flf subset.txt -r objects/

So, if your final list isn't too long, you can just do:

 mv $(grep -Flf subset.txt -r objects/) new_dir/

If that returns an argument list too long error, use:

grep -Flf subset.txt -r objects/ | xargs -I{} mv {} bar/

And if your file names can contain spaces or other strange characters, use (assuming GNU grep):

grep -FZlf subset.txt -r objects/ | xargs -0I{} mv {} bar/

Finally, if you want to exclude binary files, use:

grep -IFZlf subset.txt -r objects/ | xargs -0I{} mv {} bar/

use

grep -F -f subset.txt 

to tell grep to read from subset.txt file.

you may use find to walk the file.

find . -type f -exec grep -F -f subset.txt {} \;

or

find . -type f -exec grep -F -f subset.txt {}  +

If you want to speed up grep even more, you can set the locale in your shell before running it, i.e. use "LC_ALL=c". This will be inherited into grep and will disable Unicode processing when not necessary and in some cases can dramatically speed up grep. A great blog documenting this can be found at http://www.inmotionhosting.com/support/website/ssh/speed-up-grep-searches-with-lc-all. This trick also can speed up bash shell scripts as well, not just grep.