cat /proc/swaps | awk '/dev/ {print $1}' awk '/dev/ {print $1}' /proc/swaps a=cat /proc/swaps | awk '/dev/ {print $1}' echo $a b=awk '/dev/ {print $1}' /proc/swaps echo $b c=`cat /proc/swaps | awk '/dev/ {print $1}'` echo $c d=$(awk '/dev/ {print $1}' /proc/swaps) echo $d