Step-by-step – GCC 10.2 Installation in Debian Buster

Switching

8. 8. Switching System GCC

   Finally, to easy Managing GCC Versions use update-alternatives
   So first check where the GCC 10.2 location:

   which gcc

   And if is into /usr/local/bin then provide to relocate it to use this location for the update-alternatives setup:

   sudo mv /usr/local/bin/gcc /usr/bin/gcc-102

   This because in the ordinary PATH Env setup /usr/local/bin takes precedence over /usr/bin.
   Now install the New GCC 10.2 with:

   sudo update-alternatives --install /usr/local/bin/gcc gcc /usr/bin/gcc-102 10

   And then the System GCC with for instance:

   sudo update-alternatives --install /usr/local/bin/gcc gcc /usr/bin/gcc-9 20

   Possibly amend the above Command with the Path found on Step 2.
   Next to Switch between GCC Versions play:

   sudo update-alternatives --config gcc

   Last, to test the GCC in use:

   gcc -v



Congratulations, your GCC 10.2 should be now nicely working on Debian Buster. Good Luck! :)