#rev 2020-09-08 stroth
#rev 2018-10-30 stroth

= How can I compile/install additional software on a managed linux workstation? =

Only system administrators with elevated privileges (a.k.a. ''sudo'' or ''root'' privileges) are allowed to use the commands `apt`, `apt-get` or `dpkg` to install pre-compiled .deb-packages on a managed linux client.

As a possible way around this restriction, most software can be built from its source code and installed without elevated privileges to a custom location. Details to install software from its source code are typically listed in accompanying files named `README` and `INSTALL`, the following describes a generic installation process:


== Generic installation process ==

 * Download a source code archive, unpack it and enter the source code directory
 * Execute the command  {{{ ./configure --prefix=/home/$USER/package }}}
 . The `configure` script checks for dependencies necessary to build the software and creates the so-called `Makefile`. If it fails due to missing dependencies, install those first and set the necessary environment variables to make them available (see table below)
 * `configure --help` lists options and environment variables possible to pass to the script
 * Execute the command `make` to build the software
 * Execute the commande `make install` to install it

||''Variable''' ||'''Meaning''' ||
||`PREFIX`      ||Toplevel directory path where the software is going to be installed||
||`CPPFLAGS`    ||C preprocessor environment variable to add directories containing library headers in a custom location||
||`LDFLAGS`     ||Linker environment variable to add directories containing libraries installed in a custom location||


== Simplified example ==
The directory `opt` serves as the location for all custom-built software in the following examples.

=== Install a software where all dependencies are available ===
{{{#!highlight bash numbers=disable
./configure --prefix=/home/$USER/opt
make
make install
}}}

=== Install software depending on previously built libraries ===
{{{#!highlight bash numbers=disable
export CPPFLAGS=-I/home/$USER/opt/include
export LDFLAGS=-I/home/$USER/opt/lib
./configure --prefix=/home/$USER/opt 
make
make install
}}}

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[[CategoryLXSW]]