update script version

install-4dage

@@ -4,10 +4,17 @@ HOMEDIR=/usr/local/4dage-ffmpeg
 
 mkdir -p $HOMEDIR
 
+command_exists() {
+    if ! [[ -x $(command -v "$1") ]]; then
+        return 1
+    fi
+
+    return 0
+}
 ## command exsits
-if ! type "4dage-ffmpeg" >/dev/null; then
-    /bin/bash -c "$(curl -fsSL http://192.168.0.115:3000/zhangyupeng/4dage-ffmpeg/raw/master/4dage-ffmpeg)" >$HOMEDIR/4dage-ffmpeg   
-    ln -s $HOMEDIR/4dage-ffmpeg  
+if ! command_exists "4dage-ffmpeg"; then
+    /bin/bash -c "$(curl -fsSL http://192.168.0.115:3000/zhangyupeng/4dage-ffmpeg/raw/master/4dage-ffmpeg)" >$HOMEDIR/4dage-ffmpeg
+    ln -s $HOMEDIR/4dage-ffmpeg
 else
     /bin/bash -c "$(curl -fsSL http://192.168.0.115:3000/zhangyupeng/4dage-ffmpeg/raw/master/4dage-ffmpeg)" >$HOMEDIR/4dage-ffmpeg
 fi