I made a script to check tnsping but the if statement does not working properly. The following is the script:
ping=$(tnsping oracle1 |grep OK| awk -F" " '{print $1 }')
if [ -n $ping ]
then
echo "OK"
else
echo "NOT OK"
fi
If a execute change oracle for a non-existing oracle server I also receive "OK".
-n = The length of STRING is greater than zero
Wrap double quotes around $ping:
if [ -n "$ping" ]
then
echo "OK"
else
echo "NOT OK"
fi
Or it will undergo word splitting and globbing and resolve in the following arguments for [: '-n' and ']' when $ping is empty. which is the same as:
if [ '-n' '-n' ']'
See man test:
-n STRING
the length of STRING is nonzero
STRING
equivalent to -n STRING
-z STRING
the length of STRING is zero
And FYI you can omit the call to grep and use awk directly. And since the default Field Separator (-F) is space that can be omitted as well:
ping=$(tnsping oracle1 | awk '/OK/{print $1 }')
Neither the $ping variable nor awk are necessary, since grep can return an exit code to if:
if tnsping oracle1 | grep --quiet OK
then
echo "OK"
else
echo "NOT OK"
fi
<space><space>OK will put OK in $1. If OP was printing $2 it would not be possible.
awk answer, awk's behavior is irrelevant, and the OP was not printing $2.