How to remove error messages when searching recursively for a string?

Question

I use

find -type f -print0 | xargs -0 -n 10 grep -i searchstring

to search recursively for a string. But it also gives me error messages like "permission denied". How can I avoid such error messages and only see results?

Answer 1

Redirect standard error to /dev/null. I.e.

find -type f -print0 2>/dev/null | xargs -0 -n 10 grep -i searchstring 2>/dev/null

Answer 2

If the error messages come from find (e.g. because there's a directory you can't traverse, redirect its errors to /dev/null.

find -type f -print0 2>/dev/null | …

If the error messages come from grep (e.g. because some files are unreadable), redirect its errors to /dev/null, or pass the -s option to tell it to ignore unreadable files.

xargs -0 grep -s -i searchstring /dev/null

There's no point in limiting the number of files passed together to grep. But you should add /dev/null so that grep always sees at least two files, otherwise grep omits the file name in its output if it has only one file argument. With GNU grep or Busybox (i.e. Linux or Cygwin), you can use the -H option instead.