Question

I am trying to do a recursive search in a directory, looking for instances where the following sequence of characters occur in my code files:

-=

I am using the following command at the CLI:

grep -rn -= --include=*.hpp .

I get the following error message:

grep: invalid option -- '='
Usage: grep [OPTION]... PATTERN [FILE]...
Try `grep --help' for more information.

Unfortunately, the help dosen’t help much in addressing my question (or at least, I can’t see how it addresses my problem).

Answer 1

Try:

grep -rn --include=*.hpp -- -= .

The issue is that -= is interpreted as a command-line option. Use -- to signify end of command-line options, so the -= is interpreted as a pattern instead.