Use grep to print all lines up to a match

grep_from_start.sh

function grep_from_start () {
    if [ -z $1 -o -z $2 ]; then
        echo "Usage:\ngrep_from_start 'regex' file1 [file2 file3 ...]"
        exit 2
    fi

    for i in $(grep -n -m1 $1 "${@:2}"); do
        filename="$(cut -d':' -f1 <<< $i)"
        lnum="$(cut -d':' -f2 <<< $i)"
        omit_lines="$(( $(wc -l $filename | awk '{print $1}') - $lnum + 1 ))"
        echo "\n--\n$filename:"
        head -n -$omit_lines $filename
    done
}