Make switch-to-clang less verbose

switch-to-latest-clang

 #!/bin/bash
 
-# set -ex
-update-alternatives --install /usr/bin/c++ c++ /usr/bin/clang++-12 40
-update-alternatives --install /usr/bin/cc cc /usr/bin/clang-12 40
-update-alternatives --install /usr/bin/clang++ clang++ /usr/bin/clang++-12 40
-update-alternatives --install /usr/bin/clang clang /usr/bin/clang-12 40
-update-alternatives --install /usr/bin/ld ld /usr/bin/ld.lld-12 40
+set +e
+set -o pipefail
+
+update-alternatives --install /usr/bin/c++ c++ /usr/bin/clang++-12 40 | tee /tmp/.switch-to-clang.stdout
+update-alternatives --install /usr/bin/cc cc /usr/bin/clang-12 40 | tee -a  /tmp/.switch-to-clang.stdout
+update-alternatives --install /usr/bin/clang++ clang++ /usr/bin/clang++-12 40 | tee -a  /tmp/.switch-to-clang.stdout
+update-alternatives --install /usr/bin/clang clang /usr/bin/clang-12 40 | tee -a  /tmp/.switch-to-clang.stdout
+update-alternatives --install /usr/bin/ld ld /usr/bin/ld.lld-12 40 | tee -a  /tmp/.switch-to-clang.stdout
+
+echo compiler set to: $(readlink /etc/alternatives/c++)