Comment 0 for bug 915008

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Dan Kegel (dank) wrote : grep outputs "input file is also the output" when running grub-update

On ubuntu 12.04 alpha1, fully updated, running grub-update outputs
grep: input file `/boot/grub/grub.cfg.new' is also the output

http://bugs.debian.org/cgi-bin/bugreport.cgi?bug=651617 says two contradictory things about this:
1) that the smallest test case for this is
   sh -c 'echo foo >bar; exec >>bar; grep -q foo bar && echo found >&2'
2) that the smallest test case for this is
  grep -qr . > out

I can verify that #1 is correct, and #2 is incorrect, i.e. on the system where grub-update outputs the error message in question, only the first one fails:

dank@a3850:/tmp$ sh -c 'echo foo >bar; exec >>bar; grep -q foo bar && echo found >&2'
grep: input file `bar' is also the output

dank@a3850:/tmp$ grep -qr . > out
^C