move only if file exists in a shell script

I want to use mv to rename a file:

mv src.txt dest.txt

If the file doesn't exist, I get an error:

mv: cannot stat ‘src.txt’: No such file or directory

How do I use mv only if the file already exists?

I don't want to redirect stderr to dev/null as I'd like to keep any other errors that occur

One-liner:

[ -f old ] && mv old nu

You should test if the file exists

if [ -f blah ]; then
   mv blah destination
fi

This one liner returns successfully even if the file is not found:

[ ! -f src ] || mv src dest