Lets suppose you have a file (directory) that you would like to archive.
We can use the tar (tape archive resource) to accomplish this. This will
create a nice ascii file which can be emailed, copied, burned to cd, etc.
which contains in a nice neat package all the stuff in the directory.

Moreover, the file can be gzipped (compressed) so that it takes up less
room on your disk. The simplest form of the tar command is:

tar -cvf <archivetocreate> <stufftoarchive>

c: create
v: verbose
f: file

To extract the archive, a suitable command might be

tar -xvf <archive>

x: extract
v: verbose
f: file

For example, if we have a directory named Determinant with lots of source
files and junk we wish to archive, we would issue the command:

tar -cvf det.tar Determinant

This will create an archive named det.tar from the directory Determinant.
To extract this archive, we move to an appropriate directory and simply issue

tar -xvf det.tar

To compress the archive det.tar we can simply type

gzip det.tar

and gzip will produce a compressed archive named det.tar.gz.

NOW, this can be done all in one command, issuing (for example) 

tar cvf - Determinant | gzip > det.tar.gz

It also can be undone with one command by issuing:

gunzip -c det.tar.gz | tar xvf - 

OR, THIS can all be done by including the gzip filter when tarring:

tar -cvf det.tar.gz -z Determinant
(tar -cvzf det.tar.gz Determinant also appears to work)

and then extracting by typing

tar -xvzf det.tar.gz