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Compiling Programs from Source
Posted by: jeremy on 07-10-2003. (31435 views)
Sooner or later when using Linux you will hear the term "compile from source".
This can be intimidating the first time you hear it, but once you understand
what it is and how it works you will find it is actually quite simple. You may
ask yourself why you would want to use source when there are package
management systems like rpm and apt. While these tool do make things easy,
there are a few drawbacks to using them. First you have to depend on someone
to actually do the packaging. This means when a new version comes out you may
not be able to install it until the package is updated. You can always go grab
the source. Packages are also compiled to the lowest common denominator.
Options that many people may need are enabled and all others are disabled.
This means that if the feature you want isn't compiled into the package or you
want things installed to fit your system exactly source is the only option.
To compile a program from source you do need a few things. Some distros call
this the development package. Minimally you will need make, a compiler
(usually gcc), the appropriate libraries and a few other basic programs. If
you encounter any problems the error message should tell you what you are
missing. After correcting the problem you may need to delete the file called
config.cache before configure will recognize your changes.
We are now ready to install a basic program. The first thing you need to do is
download the source. For this article the program we are installing will be
called LinuxQuestions. You will want to download the source to the following
directory: /usr/local/src (in this case the filename is
linuxquestions.tar.gz). Once downloaded you want to do the following:
code:
tar zxf linuxquestions.tar.gz
cd linuxquestions
./configure
make
make test (optional)
make install
The first command will unzip and untar the downloaded file. You will then need
to change into the appropriate directory. Most standard packages will be
installed using the ./configure && make && make install process. You should
always read the packages instructions which will usually be found in either
README or INSTALL. By running ./configure you are doing two basic things: 1)
letting the program detect if you have everything it needs installed and where
it is 2) telling the program what options you would like it compiled with. The
options in questions can range from just a few to literally hundreds. Running
code:
./configure --help | less
will allow you to see the available options. Once configure runs through and
you have verified that there are no errors you can continue with make. This
step does the actual compiling of the program. Depending on what program you
are compiling and the machine you are on this can take anywhere from a few
seconds to a few hours. The make test step is optional, but it is a good
practice to get into. It will verify that everything is ok and the program
operates properly. It should be noted that all steps up to now should be
performed by a normal non-root user. The last step however needs to be
executed with root permissions. It needs to be run as root as this step will
actually copy the compiled programs to your system. If you made it this far
you should be able to run the program just as any other program installed on
your system. If you ever need to recompile a program you should do a make
clean (or make distclean) before doing so. This will delete files created
during the previous compile and give you a clean tree.
One notable exception to the previous instructions is perl programs. To
install perl programs from source (you can also use CPAN) you need to do the
following:
code:
tar zxf linuxquestions-perl.tar.gz
cd linuxquestions-perl
perl Makefile.PL
make
make test (optional)
make install
You will notice that many of the steps are the same with the notable exception
of ./configure vs. perl Makefile.PL.
If you ever encounter problems compiling from source the error should clearly
state what you are missing or why it is failing. If you need to post to
linuxquestions.org remember to post the complete error message you are getting
and what steps you took.
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