os.link makes a copy, not a link

[Dan M]

I'm a little bit confused. According to the sources I've looked at on the
net,
os.link('file1', 'file2')
should make a hard link from file1 to file2. But what I'm finding is that
it's actually making a copy. Am I forgetting a step or something?

Python 2.3.4 running on CentOS 4.3

[Carl Banks]

Dan M wrote:

I'm a little bit confused. According to the sources I've looked at on the
net,
os.link('file1', 'file2')
should make a hard link from file1 to file2. But what I'm finding is that
it's actually making a copy. Am I forgetting a step or something?

Python 2.3.4 running on CentOS 4.3

Are file1 and file2 on the same filesystem? Looks like os.link just
calls the OS's link system call, which, for your system, might copy the
file.

Carl Banks

[Ben Finney]

Dan M <da*@catfolks.net> writes:

I'm a little bit confused. According to the sources I've looked at on the
net,
os.link('file1', 'file2')
should make a hard link from file1 to file2. But what I'm finding is that
it's actually making a copy. Am I forgetting a step or something?

Are you sure that's what it's doing? Do you know the difference
between a copy and a hard link?

$ echo "Lorem ipsum" > foo.txt
$ ln foo.txt bar.txt
$ cp foo.txt baz.txt
$ ls -l *.txt
-rw-r--r-- 2 bignose bignose 12 2006-06-10 10:16 foo.txt
-rw-r--r-- 2 bignose bignose 12 2006-06-10 10:16 bar.txt
-rw-r--r-- 1 bignose bignose 12 2006-06-10 10:17 baz.txt
$ cat foo.txt
Lorem ipsum
$ cat bar.txt
Lorem ipsum
$ cat baz.txt
Lorem ipsum

--
\ "Good judgement comes from experience. Experience comes from |
`\ bad judgement." -- Frederick P. Brooks |
_o__) |
Ben Finney

[Nick Craig-Wood]

Dan M <da*@catfolks.net> wrote:

I'm a little bit confused. According to the sources I've looked at on the
net,
os.link('file1', 'file2')
should make a hard link from file1 to file2. But what I'm finding is that
it's actually making a copy. Am I forgetting a step or something?

Python 2.3.4 running on CentOS 4.3

It works here (Py 2.4.3 on Ubuntu Dapper Drake)

The way to check whether you are getting a copy or a hardlink is to
see whether the inode number is the same.

Otherwise it is impossible to tell whether you have a copy or a
hardlink.

import os
file("z", "w").write("test")
os.link("z", "z2")
os.stat("z").st_ino 1685186L os.stat("z2").st_ino 1685186L print os.popen("ls -li z z2").read()

1685186 -rw-r--r-- 2 ncw ncw 4 2006-06-10 08:31 z
1685186 -rw-r--r-- 2 ncw ncw 4 2006-06-10 08:31 z2

--
Nick Craig-Wood <ni**@craig-wood.com> -- http://www.craig-wood.com/nick

[Nick Craig-Wood]

Carl Banks <in**********@aerojockey.com> wrote:

Dan M wrote:

I'm a little bit confused. According to the sources I've looked at on the
net,
os.link('file1', 'file2')
should make a hard link from file1 to file2. But what I'm finding is that
it's actually making a copy. Am I forgetting a step or something?

Python 2.3.4 running on CentOS 4.3

Are file1 and file2 on the same filesystem? Looks like os.link just
calls the OS's link system call, which, for your system, might copy the
file.

The link(2) system call on linux never does that. Eg

import os
file("z", "w").write("test")
os.link("z", "/dev/shm/z")

Traceback (most recent call last):
File "<stdin>", line 1, in ?
OSError: [Errno 18] Invalid cross-device link

--
Nick Craig-Wood <ni**@craig-wood.com> -- http://www.craig-wood.com/nick

[wittempj]

I had good results with os.symlink on Solaris, see
http://docs.python.org/lib/os-file-dir.html
Dan M wrote:

I'm a little bit confused. According to the sources I've looked at on the
net,
os.link('file1', 'file2')
should make a hard link from file1 to file2. But what I'm finding is that
it's actually making a copy. Am I forgetting a step or something?

Python 2.3.4 running on CentOS 4.3