How do I test if a file has write permission?

[ChuckularOne]

The -w test will do:

if (-w FILEHANDLE) {
    print "It's writeable by my effective uid or gid!\n";
}

This code was credited to chromatic by the author. --Ed.

Originally posted as a Categorized Question.

[fx]

Another, but probably less efficient way, is to open the file in append mode. If the open fails the file COULD be read-only:

open(FILE, ">>some_file.txt") || print "File is read only";

The advantage of this way, I suppose, is that if you really want to write things to the end of the file then it's now open :)

[exussum0]

Open fails when it can't write, period. So if a directory where a file is expected or you have an NFS timeout, this will fail for non-permission reasons.

(Why would your current directory be missing? If someone else rm's it of course :)