AIX Tip of the Week

ftp Checkpoint Restart

Audience: AIX Users

Date: August 10, 2001

The AIX 4.3 ftp restart command allows you to resume an aborted file transfer at the point it stopped. This can be useful transferring large files over unstable connections because if the connection fails, you only have to transfer the remaining portion of the file.

The restart command did not work per the AIX documentation. Here's the procedure I tested. After an aborted file transfer, restart the ftp session. Log onto the remote host, and "cd" to the target directory. Then issue the commands:

restart <offset>
put <filename>

Where <offset> is the size of the aborted file, in bytes.

The restart option is not 100% portable: I've successfully tested "restart" on AIX systems and between AIX/Linux systems. It does not work on Windows, and it does not appear to be an option in the Solaris documentation.

Bruce Spencer,