From d1095a192e452bf2bac7cbb9dec47e69b9477aff Mon Sep 17 00:00:00 2001
From: Connor Olding <cloningdonor@gmail.com>
Date: Mon, 2 Aug 2021 05:17:37 -0700
Subject: [PATCH] improve isup compatiblity

---
 sh/isup | 11 ++++-------
 1 file changed, 4 insertions(+), 7 deletions(-)

diff --git a/sh/isup b/sh/isup
index cfcbb1d..a05a230 100755
--- a/sh/isup
+++ b/sh/isup
@@ -1,15 +1,12 @@
 #!/usr/bin/zsh
 # YES_ZSH
-# NO_BASH
-# NO_DASH
-
-# TODO: damned substrings. rewrite to be semi-portable.
+# YES_BASH
+# YES_DASH
 
 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 ]
+    local c="$(curl -sLI -w '%{http_code}' -o /dev/null "$1")"
+    [ -z "${c#2[0-9][0-9]}" ]
 }
 
 [ "${SOURCING:-0}" -gt 0 ] || isup "$@"