check if return value is blank

Shell Programming and Scripting
1

Hi,

i am trying to get the no of users using
nofActUsers=$(echo /usr/sbin/lsof -l | grep "/mast/data/users" )

it will return blank, if the user does nto have permissions to run the script.

Now I need to check if the valueis blank i have route to another script else the user has to continue this script.

Please help

Thanks in advance
Satya

2

Some possibilities:

nofActUsers=$(/usr/sbin/lsof -l | grep "/mast/data/users")

if [ -z "$nofActUsers" ]
then
  echo "nofActUsers is empty"
fi

or:

if [ "$(/usr/sbin/lsof -l | grep "/mast/data/users")" = "" ] 
then 
  echo "No output"
fi

or:

usr/sbin/lsof -l | grep "/mast/data/users" > /dev/null

if [ $? -eq 0 ]
then
  echo "Output not blanc, do your stuff..."
fi