Saving your input in a file

In order to keep a record of the inputs you type to Mathematica, you
can use the -record option while starting Mathematica. To use this
option you have to start Mathematica by giving the following command.
All the inputs are stored in the filename you specify.

	pascal:~: math -record filename

From within mathematica you can save the inputs or the value of
certain expressions for certain varibles to a file. These can be done
by the redirection operators which will be familiar, if you are
regular user of the Unix operating system. The redirection operators >>,
>>>, and << are analogous to >, >> and <. The following examples will
help you understand the redirection operators.

	In[12]:= x + 10*y >> tmp	writes the expression to the file

	In[13]:= !!tmp			shows the contents of file "tmp"
	x + 10*y

	In[13]:= y = 8			

	Out[13]= 8

	In[14]:= << tmp			reads the expression from the file

	Out[14]= 80 + x

Another way of storing expressions is by using the Save function. this
function allows you to save the definitions of variables and
definition in the following mannner.

	Save["filename", x, y, ....]



You can also save the image of a current state of a mathematica
session so that you can you can start from wherever you left off. This
is done by using the function Dump.

	In[1]:= Dump["filename"]

Thereafter, you can start the next session with the following command
to be at the same state it was in when you dumped it.

	math -x filename

However, it not advisable to use this because the core image produced
by the Dump function is very large. If you want to save only certain
aspects of your session to be saved, you can use the Save function in
a more economical way. The only time you will really want to use it if
you wanted to start Mathematica with the same set of definitions
loaded up.