How do I download PSRCHIVE and Tempo2 for pulsar timing on Mac Mojave? I am fairly new to pulsar astronomy, and I need to download PSRCHIVE and then Tempo2. I have followed the instructions online here: 

PulsarAstronomy.net

I'm also pretty new to linux commands/Mac terminal in general, so I think I might be missing something obvious. 
So far I have untarred the tar file, which gave me a directory 'psrsoft' in Downloads. 
I also attempted to open a psrsoft bash profile, but I don't think it worked because none of the psrsoft commands worked. 
The instructions mention '$PSRSOFT_DIR' a lot, and I am not sure where that is supposed to be or what it represents.
Right now, my goal is to get the package installation options listed and then from there install Tempo2. 

This is what psrsoft contains:

Downloads/psrsoft>bin: pkg_files, psrsoft, psrsoft-selfupdate, psrsoft-shell, psrsoft-update-index, psrsoft.py, shell_files, usr

Downloads/psrsoft>config: profile.example

Any help would be greatly appreciated.
The documentation is somewhat confusingly written. It refers to a $PSRSOFT_DIR as a shortcut to where you unpacked the tarball, which everything is done relative to but doesn't require this shell variable to be set. So there is 1 thing to do and then you can do 1 of 2 things.

The mandatory thing (as it says in the docs) is to copy the psrsoft/config/profile.example to psrsoft/config/profile and edit if necessary (I didn't need any changes but I'm running on pretty vanilla CentOS/RHEL 7; MacOS X may well be different). Then your two options are:


You can then manually "substitute in" for the unset $PSRSOFT_DIR variable e.g.  run /path/to/Downloads/psrsoft/bin/psrsoft psrchive when the docs say to run $PSRSOFT_DIR/bin/psrsoft psrchive
You can set PSRSOFT_DIR in your user's shell startup files such as ~/.bashrc or ~/.bash_profile (~ is a shortcut to your home directory which works on Unix/Linux and I assume MacOS X) by adding export PSRSOFT_DIR=/path/to/Downloads/psrsoft/. You should then be able to run the commands as shown in the documentation.