ubuntu切换gcc版本失败的一种可能原因及解决方法_there is only one alternative in link group gcc (p

安装gcc9

sudo apt install gcc-9 g++-9
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查看已安装的gcc版本

dpkg -l | grep gcc
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切换gcc版本

sudo update-alternatives --config gcc
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遇到报错

There is only one alternative in link group gcc (providing /usr/bin/gcc): /usr/bin/gcc-4.7
Nothing to configure.
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可能原因
gcc9未添加软链接

解决方法

sudo update-alternatives --install /usr/bin/gcc gcc /usr/bin/gcc-9 50 --slave /usr/bin/g++ g++ /usr/bin/g++-9
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执行该命令后再执行切换版本命令

~$ sudo update-alternatives --config gcc
There are 2 choices for the alternative gcc (providing /usr/bin/gcc).

  Selection    Path            Priority   Status
------------------------------------------------------------
* 0            /usr/bin/gcc-7   100       auto mode
  1            /usr/bin/gcc-7   100       manual mode
  2            /usr/bin/gcc-9   50        manual mode

Press <enter> to keep the current choice[*], or type selection number: 0

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若输入2，则切换到gcc版本9

查看gcc版本

gcc -v
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