What does `tar -C` mean?

Question

In the section "Installing Portage", the Gentoo installation docs say:

# tar xvjf /mnt/gentoo/portage-latest.tar.bz2 -C /mnt/gentoo/usr

What does this command do?

Answer 1

If you ever need to know what a parameter does again, try to read the man first. The command man tar, and then doing /-C will get you to the section describing what -C stands for, which in this example represents 'change directory' (i.e. sends the results of the unpacking to /mnt/gentoo/usr).

Answer 2

Tar is used to handle archives (historically saved on tapes). The x tells it to extract files from the archive, v stands for verbose, j for bzip2 archive, f indicates the file name and C tells it to change directory. See also man tar.

Answer 3

It unpacks /mnt/gentoo/portage-latest.tar.bz2 in /mnt/gentoo/usr/