regex-grep can fail if the pattern starts with a hyphen ('-')

[wesley-dean-flexion]

If the pattern for which one is searching starts with a hyphen (one or more of the '-' character), grep interprets the pattern as another flag, almost always causing the search to fail. For example:

$ grep -rinHE "-dean-flexion" .
/bin/grep: invalid argument ‘ean-flexion’ for ‘--directories’
Valid arguments are:
  - ‘read’
  - ‘recurse’
  - ‘skip’
Usage: grep [OPTION]... PATTERNS [FILE]...
Try 'grep --help' for more information.

One way to mitigate against this is the usage of the '-e' flag which signals that the next argument represents the pattern for which to search.

https://www.gnu.org/software/grep/manual/grep.html#Matching-Control

(patch / PR forthcoming)

[cytopia]

@wesley-dean-flexion thanks for the detailed explanation. I didn't know about this flag