2.2. Choose an Installation Prefix

You will see the term prefix referred to throughout this documentation and in a wide number of software packages you can download from the internet. It is also used in the GNU Coding Standard. A prefix is the path on your host computer a software package is installed under. Packages that have a prefix will place all parts under the prefix path. Packages for your host computer typically use a default prefix of /usr/local on FreeBSD and Linux.

You have to select a prefix for your RTEMS tool suite installation. The RTEMS tool suite consists of a cross tool chain (Binutils, GCC, GDB, Newlib, etc.) for your target architecture and other tools provided by the RTEMS Project. You build and install the tool suite with the RTEMS Source Builder (RSB). By default, the RSB will start the prefix path with a host operating system specific path plus rtems plus the RTEMS version, e.g. /opt/rtems/5 on Linux and /usr/local/rtems/5 on FreeBSD and macOS.

It is strongly recommended to run the RSB as a normal user and not with root privileges (also known as super user or Administrator). You have to make sure that your normal user has sufficient privileges to create files and directories under the prefix. For example, you can create a directory /opt/rtems and give it to a developer group with read, write and execute permissions. Alternatively, you can choose a prefix in your home directory, e.g. $HOME/rtems/5 or with a project-specific component $HOME/project-x/rtems/5. For more ideas, see the project sandboxing section. In this quick start chapter, we will choose $HOME/quick-start/rtems/5 for the RTEMS tool suite prefix.


The prefix must not contain space characters.