Hello and welcome to LQ.
What you describe is in Linux called an alias. For your example you would type[code]alias logs="cd $home/dev/server/tra/app/logs" on the cxommandline. Now every time you launch the command logs you will be automatically taken to the directory you specified in the alias command. If you want to have this persistent, so that you don't have to define it every time you launch a command line, add the command to your ~/.bashrc file (or its counterpart if you use a different shell than Bash).