quick question, which grep allows you to use \d? as far as I know, only GNU grep with -P option (PCRE) will allow it, otherwise you have to use [0-9] or the POSIX character set [:digit:] inside a character class
also, ERE is enabled using -E not -e, from GNU grep's man page:
-e PATTERNS, --regexp=PATTERNS
Use PATTERNS as the patterns. If this option is used multiple times or is combined with the -f
(--file) option, search for all patterns given. This option can be used to protect a pattern beginning
Interpret PATTERNS as extended regular expressions (EREs, see below).
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