scope of variable in pipe

Question

The following shell scrip will check the disk space and change the variable diskfull to 1 if the usage is more than 10% The last echo always shows

Answer 1

you can do it this way with gawk(no need to use grep). for alerts you can send email to root.

threshold=10
df -HP | awk -v t="$threshold" -v msg="" 'NR>1 && $5+0 > t{ 
    msg=msg $1" is "$5"\n"
}END{print msg}' | mail root 

or check whether there is "msg" or not first

threshold=10
result=$(df -HP | awk -v t="$threshold" -v msg="" 'NR>1 && $5+0 > t{ 
    msg=msg $1" is "$5"\n"
}END{print msg}')
if [ -n "$result" ];then
  echo "Overload"
  echo "$result" | mail root

fi