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@krl101 : That's not totally correct, rosrun expects 2 arguments : PACKAGE_NAME and EXECUTABLE_NAME but I don't exactly see the point of what OP tried to do with that command.
@notSoTechnical : For the message, if it's correctly created, you have to give the package where the msg file is and the name of the msg file without the extension .msg, both separated by a / :
rosmsg show PACKAGE_NAME/NAME_OF_YOUR_MSG_FILE