[ale] scp, rcp, tar questions

[Joseph A Knapka]

Charles Marcus wrote:
> 
> OK,
> 
> I've gotta copy some stuff (home directory for one of our users) from a
> remote server down in Fla to my local server here in Atl.
> 
> I have never used the tar beyond untarring tarballs when installing
> software, and never used the rcp command.  I am having trouble figuring out
> the syntax, and the man pages aren't much help.  I'd spend the time trying
> to figure it out myself, but this guys will be here in the morning, and I
> was just told about it, so hope someone can hold my hand...
> 
> So, what would the syntax be for tar/gzipping up a directory?  I *think it
> would be:
> 
> tar -z /home/username/* tarfile.name

tar czvf tar-file-name.tgz /dir/to/tar

Explanation:

czvf == "c"reate the tarfile, compress using g"z"ip, be
       "v"erbose (list all files added to the archive on stdout),
       and I will explicitly provide the "f"ilename of the
       tarfile as the /next/ argument. (The order of the
       czvf flags is immaterial, could be "zvcf" or whatever.)

tar-file-name.tgz must be the next argument after the "f"
flag is seen.

/dir/to/tar and all its contents (recursively) will be
tarred (and compressed on the fly). Absolute pathnames
will be converted to releative, that is, the leading
"/" will be discarded from the names in the archive. So
you must untar from root if that's where you want
things to land.

Untar that file using

tar xzvf tar-file-name.tgz

dir/to/tar and its contents will appear in the current
directory.

> One problem is, I'm on a private IP, NAT'd through to the internet, logging
> into another computer with a private IP using NAT.
> 
> So, when doing the remote copy (rcp), how do I specify the host names?  Just
> use the IPs of the routers doing the port-forwarding?

Yes. If you can log in to the box using rsh or ssh,
then rcp/scp should work as well.

> 
> Would it be:
> 
> rcp -pr user at xxx.xxx.xxx.xxx:/home/tarfile.name user at xxx.xxx.xxx.xxx:/home

rcp user at xxx.xxx.xxx.xxx:/path/to/tarfile .

should work. You don't really need -r (since you're copying
a single file), nor -p (since the tarfile will contain
the file characteristics of the files in it). You only
need the second user+hostname if you're copying to another
remote machine.
 
> Should I use scp?

Yes. The scp command would be the same. Well, except
s/rcp/scp/, natch.

Cheers,

-- Joe
"I should like to close this book by sticking out any part of my neck
 which is not yet exposed, and making a few predictions about how the
 problem of quantum gravity will in the end be solved."
 --- Physicist Lee Smolin, "Three Roads to Quantum Gravity"

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