a more general free-memory command

[????????]

Hi all,


        I fail to use the following command to free memory because the colon in 
the command does not match the colon used in the Chinese system.


        > free -m | awk '/:/ {print $2;exit}'


        I come out with a solution that matches the position instead of the 
colon:


        > free -m| sed -n '2p' | awk '{print $2}'


        I also find that similar commands are used in the IoTDB 
conf/iotdb-env.sh, so I suggest they be modified.


        Hope you find this helpful.


Bests,
Zhengming Zhang