Re: side-effect implementing the mv command

[Derick Centeno]

On Thu, 04 Mar 2010 08:45:11 -0700
Eric Blake <address@hidden> wrote:

> Hi Derick,
> 
> According to Derick Centeno on 3/4/2010 3:38 AM:
> > 
> >> [please keep replies on the list, so that others may chime in]
> 
> Thanks for adding the list back in.
> 
> >> I asked for 'ls -l' so we could see full details, such as which files are
> >> symlinks.  According to your screenshot, you happen to have plain 'ls'
> >> aliased to a coloring version; with the four files on that line colored
> >> red, black, green, and blue (I'm guessing dangling symlink, regular file,
> >> symlink, executable); but rather than having to decode your colors, an 'ls
> >> -l' would have shown that unambiguously in black and white.
> >>
> >>>
> > 
> > Thanks for the explanation regarding the function of ls -l, quite 
> > instructive.
> > Note:  All directories are on the same disk.
> > Here is your request:
> > 
> > address@hidden ~]$ cd /opt/ibm/java*/jre/plugin/ppc/ns7
> > address@hidden ns7]$ ls -l
> > total 164
> > -rwxr-xr-x 1 root root 163244 Dec 14 23:39 libjavaplugin_oji.so
> > address@hidden ns7]$ cd /usr/lib/mozilla/plugins
> > address@hidden plugins]$ ls -l
> > total 52
> > lrwxrwxrwx 1 root   root      20 Dec 15 16:59 libgnashplugin.la
> > -> ../libgnashplugin.la -rw-r--r-- 1 root   root     869 Jan 24  2008
> > libgnashplugin.lai -rwxr-xr-x 1 root   root   45000 Jan 24  2008
> > libgnashplugin.so lrwxrwxrwx 1 aguila aguila    60 Jan 13 22:39
> > libjavaplugin_oji.so
> > -> /opt/ibm/java-ppc-60/jre/plugin/ppc/ns7/libjavaplugin_oji.so 
> > address@hidden plugins]$ 
> > 
> > As you can see libjavaplugin_oji.so in the ns7 directory is a shared object 
> > not
> > a symlink. What I reported earlier is accurate.  I originally executed mv 
> > in a
> > non-standard manner on this shared object file itself.
> > For me, developing an understanding mv's program logic as it executed a 
> > symbolic
> > link back to the shared object file would be worth pursuing.  
> 
> I'm still not sure I understand the exact settings you had before you ran
> your mv command.  A transcript of the session that has the events that you
> are questioning would go a long way to understand what you are even asking
> about.
> 

I'm assuming that a formatting problem is preventing understanding.  I've 
modified the margins of my email app so that the listing you 
requested appears on one line making it easier to read.  Here it is:

address@hidden ~]$ cd /opt/ibm/java*/jre/pl*/ppc/ns7
address@hidden ns7]$ ls -l
total 164
-rwxr-xr-x 1 root root 163244 Dec 14 23:39 libjavaplugin_oji.so

The command executed within the ns7 directory was:

$ sudo mv ./libjavaplugin_oji.so /usr/lib/mozilla/plugins

Observation: It should be clear that when this command is executed (within the 
ns7 directory),libjavaplugin_oji.so is not a symlink itself.
After the execution of mv however, it is clear that libjavaplugin_oji.so -- 
within the plugins directory (as shown below) is a symlink.
address@hidden ns7]$ cd /usr/lib/mozilla/plugins
address@hidden plugins]$ ls -l
total 52
lrwxrwxrwx 1 root   root      20 Dec 15 16:59 libgnashplugin.la -> 
../libgnashplugin.la
-rw-r--r-- 1 root   root     869 Jan 24  2008 libgnashplugin.lai
-rwxr-xr-x 1 root   root   45000 Jan 24  2008 libgnashplugin.so
lrwxrwxrwx 1 aguila aguila    60 Jan 13 22:39 libjavaplugin_oji.so -> 
/opt/ibm/java-ppc-60/jre/plugin/ppc/ns7/libjavaplugin_oji.so
address@hidden plugins]$ 

The process whereby mv was used to achieve this result is abnormal insofar as 
this process is not within formal documentation which is why I'm reporting it
here for review and exploration.



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