November 7, 2004 4:51 PM
Remember old BBS's that accepted dial-in connections at 3800 bps hosting a textual community for it's users? Then you almost surely remember XModem, YModem and Zmodem. Those who have transferred files via hyperterminal will remember them as well. ZModem is a file transfer protocol that supports resuming and error-checking. Some publicly accessible unix systems only support ZModem transfers so as to ensure security woes which might arise from malicious use of FTP.

ZModem supported packages aren't that easy to find, especially for linux. You could always try Le Putty which is a modified version of Putty but with ZModem support. If the remote server is using the sz , rz programs that comes with some linux distributions and you appear to have them1, ZSSH is the way to go. It's got a good sub shell built into it that allows you to upload files to remote servers using rz at their end.

The usual method to use the rz, sz packages via ZSSH is:

For uploading:

  1. Run rz on the remote host.
  2. Hit C-@ (Control-Space) to get the zssh shell.
  3. Type in sz -e *.*2 to upload all files in your current folder to the remote server.

For downloading:

  1. Run sz with the suitable parameters on the remote host.
  2. Hit C-@ (Control-Space) to get the zssh shell.
  3. Type in rz.


[1] The lrzsz package in Fedora.
[2] The -e option specifies that sz should escape all control characters like XON, XOFF, DLE, CR-@-CR and Ctrl-X. This option is particularly significant when the remote host runs NetBSD.

Copyright © 2004-2011 Anirudh Sasikumar. All rights reserved.
Last Updated: February 19, 2005 4:40 AM