You might also consider the
test options for files (
man test for more detail)
Another alternative might be to use
stat to get the value you need.
Jim is right though, you don't just need to check the files, but the directory permissions too to ensure you can write to them. The update needed will create or remove the ile as part of the move. It can also be a nice way to get around sensitive data input in a particular place that supposedly has been locked down, i.e. the file
payroll-input.txt might have RW for the owner, Read for a group you are not in and nothing for the rest, but if you have access to update the directory, you can remove or rename the file then create your own.
I'm not advocating it, but it is something consider and make everyone panic about simple security
The output from
stat -c '%a %U %G' might give you the basics of what you need and you might parse them to decide if you should continue.
There are, however, lots of probably better suggestions before mine, such as that from
MadeInGermany.
Just more options.
Kind regards,
Robin