open: fix for MacOS and add jpg

diff --git a/open b/open
index dd6be3d..a965886 100755 (executable)
--- a/open
+++ b/open
@@ -1,11 +1,28 @@
 #!/usr/bin/env bash
 
+# Use the built-in open command on MacOS.
+UNAME=$(uname)
+case $UNAME in
+    *Darwin*) exec open "$@";;
+esac
+
+openwith() {
+    file="${1}"
+    application="${2}"
+    if [[ -n "${application}" ]]; then
+        if which "${application}" > /dev/null ; then
+            setsid nohup ${application} "${f}" > /dev/null 2> /dev/null 
+            return
+        fi
+    fi
+    setsid nohup xdg-open "${f}" > /dev/null 2> /dev/null 
+}
+
+# Determine what command to run based on file extension.
 for f in "$@"; do
-    lowercased=`echo "$f" | sed 's/./\L&/g'`
-    case $lowercased in
-        *.pdf) 
-            setsid nohup evince "${f}" > /dev/null 2> /dev/null;; 
-        *)
-            setsid nohup xdg-open "${f}" > /dev/null 2> /dev/null;; 
+    case ${f,,} in
+        *.jpg) openwith "${f}" ristretto;;
+        *.pdf) openwith "${f}" evince;;
+        *) openwith "${f}";;
     esac
 done