[ale] scp, rcp, tar questions

[hirsch at zapmedia.com]

Charles Marcus writes:
 > 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 -czf /home/directory tarfile.tar.gz

 > 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?

Any name that resolves to the given machine should work, including the
IP number.  It would be better to use scp, though.

 > Would it be:
 > 
 > rcp -pr user at xxx.xxx.xxx.xxx:/home/tarfile.name user at xxx.xxx.xxx.xxx:/home
 > 
 > Should I use scp?

Yes.  Even better, use tar and ssh (or rsh):

machine1> tar -czf - /home/directory | ssh machine2 (cd /home; tar -xzf - )

should do the trick.  You may substitue rsh for ssh if you must.  The
-f option means use a file, and if the file is named - use stdin or
stdout.  So the first tar puts the output on stdout and the second tar
reads it from stdin.  You never need to create a tar file.  

Even easier, assuming ssh (or rsh) is setup correctly,

machine1> rsync -a -e ssh /home/directory machine2:/home

should copy all of directory to machine2:/home.  In the future, if you
need to update it:

machine1> rsync -a -e ssh --delete /home/directory/ machine2:/home/directory/

Please note the location of all '/'s in that line.  It is very easy to
forget one of them and get files in the wrong place.

--Michael

---
This message has been sent through the ALE general discussion list.
See http://www.ale.org/mailing-lists.shtml for more info. Problems should be 
sent to listmaster at ale dot org.