Making a script to run several nmap scans and save out put to a file

I was wondering how to make a bash script to do several nmap scans at once and save the output so I can read it laster, example of what I was doing,

Echo " enter target up "
Read IP
nmap  -A $IP
nmap - sV $IP
nmap - O $IP

i wanted to have these run and either save to one output file to cat later or if that's not possible then 3 different files to cat either or, I'm pretty new at this, I tried nmap -A $IP -oN root/home/nmap after each scan and that didn't work idk I'm stuck

You simply redirect the entire script's output to a file, like

./script_nmap.sh > totaloutput

Thank you I'll give it a try