OSX bash script to execute once on Terminal.app open

Question

I am using OSX on a Mac and use Terminal quite often. I have built a few startup scripts that execute on shell open with the .bash_profile file. However, I would like to be able to have one of them run only on the open of the first shell session when I launch the Terminal app. I can't figure out how to have it launch just once on Terminal app open (the first bash shell opened) but not on subsequently opened new shells.

Answer 1

Here's how I just did it:

I added this to .bash_profile

# Only do this in the first terminal opened termsOpen=$(who | grep 'ttys' | wc -l) if (( $termsOpen < 2 )); then echo "This is echoed in the first tty opened only" fi 

So, upon launching the terminal the first time, I get this output:

Last login: Mon Sep 26 08:30:42 on ttys001 This is echoed in the first tty opened only 

When I open another terminal (and thus have two terminal windows open at the same time) I get this output:

Last login: Mon Sep 26 08:33:43 on ttys000 

**How it works:**
Every time a new terminal window is opened `.bash_profile` is sourced. This command

who | grep 'ttys' | wc -l 

simply counts the number of terminal windows that are open. If they are lower than 2 (in other words; there is only one terminal window active), then echo This is echoed in the first tty opened only

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Version info:

OS X Version: 10.11.5

bash --version GNU bash, version 3.2.57(1)-release (x86_64-apple-darwin15)