I downloaded Postman for Linux (from https://www.getpostman.com/apps), unpacked .tar.gz file into ~/bin/postman and then tried to execute ~/bin/postman/Postma
~/bin/postman
~/bin/postman/Postma
Download latest version of postman from https://www.postman.com/downloads/ then after tar.gz file gets downloaded follow below commands
$ tar -xvzf Postman-linux-x64-7.27.1.tar.gz $ cd Postman $ ./Postman