tar.info: problems with exclude

exclude

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Problems with Using the `exclude' Options
-----------------------------------------

Some users find `exclude' options confusing.  Here are some common
pitfalls:

   * The main operating mode of `tar' does not act on a file name
     explicitly listed on the command line, if one of its file name
     components is excluded.  In the example above, if you create an
     archive and exclude files that end with `*.o', but explicitly name
     the file `dir.o/foo' after all the options have been listed,
     `dir.o/foo' will be excluded from the archive.

   * You can sometimes confuse the meanings of `--exclude' and
     `--exclude-from'.  Be careful: use `--exclude' when files to be
     excluded are given as a pattern on the command line.  Use
     `--exclude-from' to introduce the name of a file which contains a
     list of patterns, one per line; each of these patterns can exclude
     zero, one, or many files.

   * When you use `--exclude=PATTERN', be sure to quote the PATTERN
     parameter, so GNU `tar' sees wildcard characters like `*'.  If you
     do not do this, the shell might expand the `*' itself using files
     at hand, so `tar' might receive a list of files instead of one
     pattern, or none at all, making the command somewhat illegal.
     This might not correspond to what you want.

     For example, write:

          $ tar -c -f ARCHIVE.TAR --exclude '*.o' DIRECTORY

     rather than:

          # _Wrong!_
          $ tar -c -f ARCHIVE.TAR --exclude *.o DIRECTORY

   * You must use use shell syntax, or globbing, rather than `regexp'
     syntax, when using exclude options in `tar'.  If you try to use
     `regexp' syntax to describe files to be excluded, your command
     might fail.

   *  In earlier versions of `tar', what is now the `--exclude-from'
     option was called `--exclude' instead.  Now, `--exclude' applies
     to patterns listed on the command line and `--exclude-from'
     applies to patterns listed in a file.