From: Han Holl <han.holl@...>
Date: 2006-10-11T17:37:05+09:00
Subject: FileUtils.touch not consistent with system('touch')

Hi,

I have a world-writable file, not owned by me, that I try to touch:

-rwxrwxrwx 1 root root 0 Oct 11 10:29 /tmp/file

ruby -rfileutils -e 'FileUtils.touch("/tmp/file")'
/usr/lib/ruby/1.8/fileutils.rb:1014:in `utime': Operation not
permitted - /tmp/file (Errno::EPERM)
        from /usr/lib/ruby/1.8/fileutils.rb:1014:in `touch'
        from /usr/lib/ruby/1.8/fileutils.rb:1012:in `touch'
        from -e:1

but:
ruby -e 'system("touch /tmp/file")'

succeeds.

The reason is that File.utime cannot be called with a NULL argument.
Linux (and I assume this is Posix) allows a utime call with NULL if
the file is writeable,
but to change the time a process must have special privileges.
With the current File.utime FileUtils cannot implement this.

Cheers,

Han Holl