Bash: escape characters in backticks

I'm trying to escape characters within backticks in my bash command, mainly to handle spaces in filenames which cause my comma开发者_高级运维nd to fail.

The command I have so far is:

grep -Li badword `grep -lr goodword *`

This command should result in a list of files that do not contain the word "badword" but do contain "goodword".

Your approach, even if you get the escaping right, will run into problems when the number of files output by the goodword grep reaches the limits on command-line length. It is better to pipe the output of the first grep onto a second grep, like this

grep -lr -- goodword * | xargs grep -Li -- badword

This will correctly handle files with spaces in them, but it will fail if a file name has a newline in it. At least GNU grep and xargs support separating the file names with NUL bytes, like this

grep -lrZ -- goodword * | xargs -0 grep -Li -- badword

EDIT: Added double dashes -- to grep invocations to avoid the case when some file names start with - and would be interpreted by grep as additional options.

How about rewrite it to:

grep -lr goodword * | grep -Li badword