[Q] How to use "grep" to search the "build.prop" topic

Hey guys! :D
I am new to this forum, and needed some extra help
I am trying to add a line of text to "Build.prop" from a file Test.sh

Code:

echo "#Test" >> /system/build.prop

But if you run the code again, the same line is created

I'm trying to do it this way, but does not give any results

Code:

if [ $(grep "#Test" /system/build.prop) ]; then
        sed -i '/Test/d' /system/build.prop;
else
        echo "#Test" >> /system/build.prop;
fi

Can someone help me solve this problem? :confused: :D

mobile