grepe

#!/bin/bash
# (bash is needed for array support)
USAGE="Usage: ${0##*/} [OPTION]... [--] PATTERN [PATTERN]... [--] [FILE]..."
help() {
  echo "$USAGE"
  cat <<'/help'
Multi-pattern grep (like `grep -E PAT1\|PAT2...` or `grep -e PAT1 -e PAT2 ...`)

Added/removed options (see `grep --help` for a full list of options):
  -e, --regexp=PATTERN  REMOVED, use standard grep instead
  -f, --file=FILE       REMOVED, use standard grep instead
  --split               Force use of the `grep -e PAT1 -e PAT2 ...` format

/help
  version
}

usage() {
  printf '%s\nTry `%s --help` for more information.\n' "$USAGE" "${0##*/}" >&2
  exit 2
}

version() {
  echo 'Part of misc-scripts: https://github.com/adamhotep/misc-scripts'
  echo 'grepe 1.0.20200124.1, Copyright 2010+ by Adam Katz, GPL v2+'
  exit
}

if [ $# = 0 ]; then usage; fi
if [ "$*" = "-h" ]; then help; fi	# support literal `grepe -h` standalone

# programmatically determine GNU grep's options (see below for non-GNU)
GREP_OPTION_LIST="$(grep --help 2>&1 |awk '
  /^ *-[a-zA-Z_0-9][ ,]/ {
    sub(/^ *-/, "")
    sub(/,.*/,"",$1)
    if ($2 ~ /^--[^ ]*=/) $1 = $1 ":"	# option requires an argument
    print $1
  }
  $1 == "-NUM" {
    print "0123456789"
  }
' |sort |xargs |sed 's/ //g')-:"

# Non-GNU grep: assume solely POSIX arguments
# via http://pubs.opengroup.org/onlinepubs/9699919799/utilities/grep.html
if [ "${#GREP_OPTION_LIST}" -lt 14 ]; then
  GREP_OPTION_LIST="EFclqinsvxe:f:"
fi

split= num= ere='-G' delim='\|' sep='--'
args=() pat=()

while getopts $GREP_OPTION_LIST OPT; do
  case "$OPT$OPTARG" in
    ( [0-9] )   	num="$num$OPT" ;;		# bug: `-1a2` = `-a -12`
    ( [EP]|-extend*|-perl*)	ere="-$OPT" delim='|' ;;	# ERE or PCRE
    ( [ef]* )   	echo "Use grep for \`-$OPT\`" >&2; exit 2 ;;
    ( -file*|-regex*)	echo "Use grep for \`--${OPTARG%%=*}\`" >&2; exit 2 ;;
    ( F|-fixed* )	ere='-F' split=1 sep='' ;;	# plaintext match
    ( G|-basic* )	ere='-G' delim='\|' ;;		# BRE - assumes GNU grep
    ( -help* )		help ;;
    ( [^-]?* )  	args+=("-$OPT" "$OPTARG") ;;	# has option
    ( -split* ) 	split=1 sep='' ;;		# no assumed GNU grep
    ( V | -ver* )	version ;;
    ( \? )		usage ;;
    ( * )		args+=("-$OPT$OPTARG") ;;	# long or no option
  esac
done
shift $((OPTIND-1))

if [ "${num:--1}" -ge 0 ]; then args+=("-$num"); fi

[ "$split$ere" = 1-P ] && echo "grepe: ignoring --split for -P" >&2
[[ "$ere" = -G && "$GREP_OPTION_LIST" != *G* ]] && ere='' split=1 sep=''

while [ "$#" != 0 ] && [ ! -e "$1" ]; do	# -e needed for dirs & grep -r
  [ "$1" = -- ] && shift && break
  [ "$split" = 1 ] && pat+=(-e "$1") || pat="${pat:+$pat$delim}$1"
  shift
done

exec grep "${args[@]}" $ere $sep "${pat[@]}" "$@"