Installing programs in Linux:

When you get a Linux program, it's usually in a .tar.gz (or .tgz) file, which
is a TAR archive that has been further made into a GZIP archive. Before
anything else, you must uncompress these archives, just like you need to
uncompress a ZIP in DOS before you can use the files in it. The usual way of
handling .tar.gz files in Linux is with this command:

gzip -cd filename | tar xfv -

(Where filename is the filename of the .tar.gz file.) The x option tells tar
to extract the archive (it must be the first option). The v option tells tar
to be verbose (so it provides more info).

Note that newer versions of tar have a "z" option which lets you filter the
file through GZIP first, which allows you to just use a plain tar command
instead of having to pipe gzip output through tar. So, the new method for
extracting .tar.gz files in Linux is with this command:

tar xfvz filename

Much simpler, isn't it? Again, filename is the filename of the .tar.gz file.

Because of all the varieties of different Linux kernels and configurations,
rarely do you just download a program and run it, as you would do with DOS.
Rather, Linux programs, once you unzip them into some directory, are usually
installed using three commands. In the order you should run them, they are:

./configure
make
make install

The "configure" command configures the program to your system in preparation
for building it. It creates makefiles in preparation for the make command,
and custom-creates those makefiles for your system. Although the configure
command can potentially take several parameters (depending on what program
you're configuring), you can usually run it with no parameters. The most
common parameter used with configure is --prefix, which allows you to specify
a directory into which the program should be installed. For example, if you
wanted to install the program into /usr/bin, you would type:

./configure --prefix=/usr/bin

Often, you might want to install a program into your home directory, and you
can simply use the tilde for a --prefix parameter to indicate this:

./configure --prefix=~

The "make" command builds the program, compiling the source code into binary
executables. Finally, "make install" actually installs those executables.
This is the standard procedure for installing any Linux program which comes
in source code form.

A final, fourth command is optional: "make clean". This command usually
removes any temporary files created during the previous three commands. This
is not necessary for the program to function, but it gets rid of the files
you don't need anymore and saves some disk space, so it's good practice to
run it when you're done.