hgrep

#!/bin/bash

#
# hgrep - grep with headers
#
# written by Krishna Roskin, updated by Phillip Dexheimer (pdexheimer@gmail.com), 2019
#

if [ $# -eq 0 ] || [ "$1" = "-h" ] || [ "$1" = "-?" ]; then
  >&2 cat <<EOHelp
hgrep - grep with headers

Displays the first line (the header line) of the file being grepped, 
before searching for the pattern.  Arguments are the same as grep

User Beware:
 1) Any shell aliases for grep are ignored
 2) If the input is stdin, the first line will be consumed.  This
    will cause, eg, hgrep -n to be off by one
 3) If multiple input files are supplied, only the first line of
    the first will be displayed
EOHelp
exit 1
fi

# Remove any arguments that begin with -
ARGS=${@##-*}
ARGS=($ARGS)

# The input is always the second file (if present)
# If there is no second file, it's stdin
FILE=${ARGS[1]:--}

exec 6<&0  # save stdin into filhandle 6
if [ "$FILE" != "-" ]; then
  exec < $FILE # redirect the file to stdin
fi
tmp=$IFS
IFS=$'\n'
read header
echo $header
IFS=$tmp
exec 0<&6 6<&- # Restore stdin and delete filehandle 6

exec grep "$@"