And in that case, neither would system "mv"....

Behavior of this function varies wildly depending on your system implementation. For example, it will usually not work across file system boundaries, even though the system mv command sometimes compensates for this.

The docs are fuzzy, and probably deserve patching.

The mv command has issued a cp behind the scenes to rename a file from one volume to another for at least 20-ish years of Unix history.

However, I have yet to see an mv command that would transparently handle the moving of a directory from one filesystem to another. Are you aware of even one?

-- Randal L. Schwartz, Perl hacker

However, I have yet to see an mv command that would transparently handle the moving of a directory from one filesystem to another. Are you aware of even one?

I'm aware of three examples:
• Mandrake Linux 8.2
  Edited output from mount:
  /dev/scsi/host0/bus0/target0/lun0/part9 on /tmp type reiserfs (rw)
  /dev/scsi/host0/bus0/target1/lun0/part2 on /home type reiserfs (rw)
  # mkdir /home/test
  # touch /home/test/testing
  # ls -la /tmp/test
  ls: /tmp/test: No such file or directory
  # mv /home/test /tmp
  # ls -la /tmp/test
  total 8
  drwxr-xr-x 2 root root 72 Jun 28 09:26 ./
  drwxrwxrwt 106 root root 6736 Jun 28 09:26 ../
  -rw-r--r-- 1 root root 0 Jun 28 09:26 testing
  
• HP-UX 11.00
  Edited output from mount:
  /tmp on /dev/vg00/lvol4 delaylog,nodatainlog on Fri May 10 15:37:38 2002
  /home on /dev/vg00/lvol5 delaylog,nodatainlog on Fri May 10 15:37:38 2002
  # mkdir /home/test
  # touch /home/test/testing
  # ls -la /tmp/test
  /tmp/test not found
  # mv /home/test /tmp
  # ls -la /tmp/test
  total 10
  drwxr-xr-x 2 root sys 96 Jun 28 09:40 .
  drwxrwxrwx 9 bin bin 5120 Jun 28 09:41 ..
  -rw-r--r-- 1 root sys 0 Jun 28 09:40 testing
  

I've tried it on a FreeBSD 4.5 box, and that also worked.
Cheers.
davis
Is this going out live?
No, Homer, very few cartoons are broadcast live - it's a terrible strain on the animator's wrist