#!/usr/bin/zsh
# YES_ZSH
# NO_BASH
# NO_DASH

# TODO: damned substrings. rewrite to be semi-portable.

isup() { ### @-
    ### return 0 if a given website returns a 2xx HTTP code.
    local c
    curl -sLI -w '%{http_code}' -o /dev/null "$1" | read -r c
    [ "${c:0:1}" -eq 2 ]
}

[ "${SOURCING:-0}" -gt 0 ] || isup "$@"