Re: renameutils 0.6.0

[Bob Proulx]

Oskar Liljeblad wrote:
> Brian Hall wrote:
> > The order of the arguments passed my imv doesn't work:
> > 
> > > strace imv setup-gentoo-chroot
> > execve("/usr/bin/mv", ["mv", "setup-gentoo-chroot", "--", 
> > "setup-gentoo-chroot.sh"], [/* 68 vars */]) = 0
> > uname({sys="Linux", node="syrinx", ...}) = 0
> > 
> > mv: when moving multiple files, last argument must be a directory
> > Try `mv --help' for more information.
> 
> How can the above execve-call lead to the error message above?

The execve call above is:

  /usr/bin/mv setup-gentoo-chroot -- setup-gentoo-chroot.sh

The mv command has two forms:

  info coreutils mv

     mv [OPTION]... SOURCE DEST
     mv [OPTION]... SOURCE... DIRECTORY

    It is an error if the last argument is not a directory and more than
    two files are given.

The first one is for when there are two non-option arguments and the
second one is for when there are three or more non-option arguments.
Because the example has three non-option arguments the last argument
must be a directory.  It is not and so the error is generated.

> I cannot explain that, other than that mv thinks "--" is a file
> of itself.

GNU mv allows options to appear anywhere on the line.  But that is not
standard nor portable.  It is a system dependent behavior.  Standard
commands require options to occur before non-arguments on the command
line.

See guideline 9 from the standards documentation:

  
http://www.opengroup.org/onlinepubs/009695399/basedefs/xbd_chap12.html#tag_12_02

> My mv from coreutils 5.2.1 doesn't do that, not even
> if there's a local file "--".

GNU mv will conform strictly to standard behavior if POSIXLY_CORRECT
is set.

  touch a
  mv a -- b
  touch a
  POSIXLY_CORRECT=1 mv a -- b
  mv: when moving multiple files, last argument must be a directory
  Try `mv --help' for more information.

Bob