Most Open Source software is distributed as compressed tarballs containing source code and build scripts to compile and install the software.

These tarballs are generally compressed using either gzip or bzip2. GNU tar supports these compression formats, and makes it easy to decompress such files. For example, to unpack a gzip compressed tarball:

$ tar zxvf /path/to/tarball.tar.gz
	

The z option tells tar to use the gzip alghorithm, and the x option tells tar to extract the file. To extract a bzip2 compressed file use GNU tar's j option:

$ tar jxvf /path/to/tarball.tar.bz2
	

Although GNU tar supports these compression alghorithms, several other tar implementations don't. To extract compressed tarballs on machines with such tar implementations, you first need to decompress the file, and then extract the contents.

For a gzip compressed tarball:

$ gunzip /path/to/tarball.tar.gz
	

For a bzip2 compressed tarball:

$ bunzip2 /path/to/tarball.tar.bz2
	

As an alternative, you can also use the '-d' (decompress) argument to the gzip and bzip2 commands.

After decompression, you can extract the contents by calling tar without giving a compression argument:

$ tar xvf /path/to/tarball.tar
	

Usually the build scripts are generated using GNU autoconf and automake. automake is used to generate GNU Coding standard compliant Makefile.in files. autoconf produces self-contained configure scripts which can then be used to adapt, build and install the software on the target system.

The usual way of building and installing software from source looks something like this:

$ tar zxvf snow-2.0.3.tar.gz
$ cd snow-2.0.3
$ ./configure
$ make
$ su
# make install
      

The ./configure command will check for both optional and mandatory dependencies. It will also adapt the source code to the target system (think system architecture, installed libraries, compiler flags, install directories, ...). If an optional dependency is missing, it will disable compilation to that dependency. In the case of missing required dependencies, it will print the error and exit.

According to GNU standards, the commands above would install the 'snow' application under /usr/local. If you want to install the application under some other directory structure, for example /opt, the configure command would look like:

$ ./configure --prefix=/opt
      

Try ./configure --help to see all possible configure arguments.

The configure command also generates Makefiles which make uses to compile and install the software. The Makefile usually contains several 'build targets' which you can call by giving them as an argument to make. Often used targets include 'all' which is usually the default action, 'clean' to clean up (remove) built object files from the source tree, and 'install' to install the software after the build stage.

It's possible to install the built software under a different directory than it was configured for. This is for useful if you want to build the software on one machine, and install it on another:

$ tar zxvf snow-2.0.3.tar.gz
$ cd snow-2.0.3
$ ./configure --prefix=/opt/snow
$ make DESTDIR=/tmp/snow_tmp install
	    

This technique is often used to build software on one machine, and install it onto multiple others. In the above case, the /tmp/snow_tmp directory would only contain files installed by snow-2.0.3.

$ cd /tmp/snow_tmp
$ tar zcf snow_2.0.3_built.tgz opt/
      

The c option (as opposed to the previously mentioned x option) to tar tells it to create a new archive.

If you copy the resulting tarball to the target machines in, let's say, the /tmp directory, you can execute the following commands to install the snow software into /opt/snow:

# cd /
# tar zxvf /tmp/snow_2.0.3_built.tgz