On a Mac anytime you upgrade Xcode or the operating system, there appears to be a chance of the command line tools being removed.
in the terminal window, will install the tools, this can also be done inside the xcode application.
[~] xcode-select -h Usage: xcode-select [options] Print or change the path to the active developer directory. This directory controls which tools are used for the Xcode command line tools (for example, xcodebuild) as well as the BSD development commands (such as cc and make). Options: -h, --help print this help message and exit -p, --print-path print the path of the active developer directory -s <path>, --switch <path> set the path for the active developer directory --install open a dialog for installation of the command line developer tools -v, --version print the xcode-select version -r, --reset reset to the default command line tools path
if you have more than one set of tools installed (such as beta version) the
-s, --switch flag is also helpful to get it pointed to one you want to use (or if the version it was pointed to was removed)