FYI, the mongo
shell script is no longer included in the tarball from 6.0 onward. If you want to follow step 4 of the original instructions to set your username and password, then you should do the following between steps 3 and 4:
wget https://downloads.mongodb.com/compass/mongosh-1.8.0-linux-x64.tgz
tar zxf mongosh-1.8.0-linux-x64.tgz
ln -s $PWD/mongosh-1.8.0-linux-x64 mongosh
Then in step 4, replace the first line with:
~/apps/mongoapp/mongosh/bin/mongosh localhost:55555/admin