To execute command as root on remote computer with ip 10.19.148.65 using ssh

To execute command as root on remote computer with ip 10.19.168.65
> ssh root@10.19.148.65 "ls -la"

To execute text replacement on remote computer using perl script
> ssh root@10.19.148.65 "perl -p -e 's/oldtext/newtext/g' oldfile >newfile"