This article will show you how to install PGP Command Line on macOS.
Resolution
To install PGP Command Line on a macOS system:
Close all applications.
Download the installer application, PGPCommandLine[version]MacOSX.tgz, to your desktop.
Double-click on the file PGPCommandLine[version]MacOSX.tgz.
If you have Stuffit Expander, it will automatically first uncompress this file into PGPCommandLine105MacOSX.tar, and then untar it into PGPCommandLine[version]MacOSX.pkg.
Double-click on the file PGPCommandLine[version]MacOSX.pkg.
Follow the on-screen instructions.
The Mac OS X PGP Command Line application, pgp, is installed into /usr/bin/.
After you run PGP Command Line for the first time, its home directory will be created automatically in the directory $HOME/Documents/PGP. This directory may already exist if PGP Desktop for Mac OS X is already installed on the system.