I have just installed gcc 4.7 from ppa repository. Ubuntu 12.04 already comes with 4.6. When I use command:

gcc --version

It tells me it is 4.6.3 to be exact.

I have no idea of how to launch the 4.7 compiler. In fact, I wouldn't mind erasing the former version and stay with 4.7 only (I guess that wouldn't be a problem).

How can I fix this?

  • do you have synaptic on your system?! – user61928 Sep 27 '12 at 8:40
  • If i uninstall gcc from synaptic, when I call gcc into console version 4.7 will show up? Just as easy as that? – Roman Rdgz Sep 27 '12 at 9:05
  • yes but you must check which version you are removing – user61928 Sep 27 '12 at 9:08
  • you have to remove you old gcc first sudo apt-get remove gcc* then install the newer version – blade19899 Sep 27 '12 at 10:10

Use update-alternatives (from CLI) or galternatives (from GUI) to set the default for gcc.

If you don't have them, install with: sudo apt-get install galternatives.
I would use the GUI version, it is more simple for a beginner.

From CLI:
sudo update-alternatives --install /usr/bin/gcc gcc /path/to/newer/gcc 40
sudo update-alternatives --install /usr/bin/gcc gcc /path/to/older/gcc 30
sudo update-alternatives --config gcc

  • I have installed galternatives but I have no idea of what I should do with it. gcc is not listed among the list of alternatives. 'C++' is, for example, and if I click I see only one option, using /usr/bin/g++. But I don't know If adding a new option to the newer g++ – Roman Rdgz Sep 27 '12 at 10:59
  • See the CLI commands. Customize them, to fit your needs. – Frantique Sep 27 '12 at 12:31
  • I have had a look at /usr/bin looking for the newer g++, and I found that I currently have gcc4.5, 4.6 and 4.7, and then there is a link to executable called gcc, which points to gcc-4.6. Same for g++. Wouldn't it be easier to modify this link from console (don't know how to) to point to 4.7, and leave everything else as it is? – Roman Rdgz Sep 27 '12 at 13:17
  • Roman: for this is made the alternatives to not to modify anything in the filesystem. Try to read a little bit about it, it worths... – Frantique Sep 27 '12 at 13:25

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