Cfxtrjtrk

I just installed Lubuntu 18.04 LTS. There are two options for installing gcc: gcc-7 and gcc-8. Both are available from apt-get install out of the box.

Even after I installed gcc-8, the system is still going to install gcc-7 when I install other packages such as build-essential.

Since gcc-8 is newer, is there a way to make it install gcc-8 and gcc-8 only?

gcc-7 and gcc-8 will happily co-live together.

I would suggest to let gcc-7 be installed, for satisfying build-essential and perhaps other dependent packages, and configure gcc-8 to be your default gcc installation.

Use update-alternatives for having gcc redirected automatically to gcc-8:

sudo update-alternatives --install /usr/bin/gcc gcc /usr/bin/gcc-7 700 --slave /usr/bin/g++ g++ /usr/bin/g++-7

sudo update-alternatives --install /usr/bin/gcc gcc /usr/bin/gcc-8 800 --slave /usr/bin/g++ g++ /usr/bin/g++-8

This will give you the convenience of gcc being at the latest version, and still you will be able to invoke gcc-7 or gcc-8 directly.

If you'll wish to change the default gcc version later on, run sudo update-alternatives --config gcc. It will bring a prompt similar to this, which lets you pick the version to be used:

There are 2 choices for the alternative gcc (providing /usr/bin/gcc).



  Selection    Path            Priority   Status

------------------------------------------------------------

* 0            /usr/bin/gcc-8   800       auto mode

  1            /usr/bin/gcc-7   700       manual mode

  2            /usr/bin/gcc-8   800       manual mode



Press <enter> to keep the current choice[*], or type selection number: 

The higher priority is the one that is picked automatically by update-alternatives.

GCC 8 on Ubuntu 16.04

sudo add-apt-repository ppa:ubuntu-toolchain-r/test

sudo apt-get update

sudo apt-get install gcc-8 g++-8

gcc-8 --version

gives 8.1.0 as of 2018-11. See also: How to install gcc-7 or clang 4.0?