free -m && awk == nice

#!/bin/sh
OFF="$1"
UNIT="$2"

OUTPUT_FROM_DF_AND_AWK=$(free -m | awk 'IF NR == 2 {print $4"%s%s"$2"%s\n"}')

for LINE in $OUTPUT_FROM_DF_AND_AWK
do	
	printf $LINE "$UNIT" "$OFF" "$UNIT";echo " ";
	
done

peter@E5410:~$ memory.sh " av " "MB"
2643MB av 7799MB