simplify monitor

sh/monitor

@@ -2,22 +2,12 @@
 monitor() {
     local time=$1
     local cmd=$2
-    local lines=0
-    local elines=0
     local stop=0
     trap stop=1 INT
+    echo -en "\e[H\e[2J"
     while [ $stop -eq 0 ]; do
-        [  $lines -gt 1 ] && echo -en "\e[${lines}A"
-        [ $elines -gt 0 ] && echo -en "\e[${elines}A"
-        lines=0
-        elines=0
-        ($cmd | fold -w $COLUMNS | while read -r; do
-            echo -E "$REPLY"
-            let lines++
-        done) 2>&1 | fold -w $COLUMNS | while read -r; do
-            echo -E "$REPLY" >&2
-            let elines++
-        done
+        echo -en "\e[1J\e[H"
+        $cmd 2>&1 | fold -w $COLUMNS | tail -$((LINES-1))
         sleep $time || break
     done
 }