Operating systems

The ancient tar is de-facto packing utility in all *nixes. Originally it was used for tape backups, but since tape backups are pretty much in the past, it is used solely for file transfers. Pretty much everything distributed for a *nix in the net is a single compressed tar-archive. However, there is a hidden side-effect in it. Put a colon-character (:) in the filename and tar starts mis-behaving.

Example:

tar tf 2014-02-04_12\:09-59.tar
tar: Cannot connect to 2014-02-04_12: resolve failed

What resolve! The filename is there! Why there is a need to resolve anything?

Browsing the tar manual at chapter 6.1 Choosing and Naming Archive Files reveals following info: "If the archive file name includes a colon (‘:’), then it is assumed to be a file on another machine" and also "If you need to use a file whose name includes a colon, then the remote tape drive behavior can be inhibited by using the ‘--force-local’ option".

Right. Good to know. The man-page reads:

Device selection and switching:
--force-local
              archive file is local even if it has a colon

Let's try again:

tar --force-local tf 2014-02-04_12\:09-59.tar
tar: You must specify one of the `-Acdtrux' or `--test-label'  options

Hm.. something wrong there. Another version of that would be:

tar -t --force-local f 2014-02-04_12\:09-59.tar

Well, that hung until I hit Ctrl-d. Next try:

tar tf 2014-02-04_12\:09-59.tar --force-local

Whooo! Finally some results.

I know that nobody is going to change tar-command to behave reasonably. But who really would use it over another machine (without a SSH-pipe)? That legacy feature makes things overly complex and confusing. You'll get my +1 for dropping the feature or changing the default.