[Toybox] Endless grep corner cases...

[Rob Landley]

Does grep -F support the empty regex ("") matching everything? Yes it  
does! How about 'grep -Fx "" filename' and that never matches anything.  
Same for grep -o "" and grep -w "".

here's a fun one:

   touch empty
   grep -f empty test.txt

Does not block reading from stdin (I.E. not eating test.txt as a  
regex), but it doesn't match anything in test.txt either (I.E. does not  
treat empty as a "" regex line). However, "echo > empty" (creating a  
file containing just a newline) _does_ do the "" matching everything  
behavior.

Not quite sure what the right behavior is. The posix guys never  
actually try weird stuff, it seems. Trying to make it all work...

Test suite updated for all but that last one, because I'm not quite  
sure what the proper behavior _is_ there yet...

Rob

 1376202216.0