Flag Semaphore in Bash
(click the video to play on YouTube)
No outside dependencies, but requires Bash 4.0 or greater.
Usage
The first argument is the string you want to spell out letter by letter, with support for numbers.
$ ./semaphore.sh "Hello world.";
Alternatively, you can send specific commands for specific signals. The following commands are supported:
$ ./semaphore.sh REST;
$ ./semaphore.sh ERROR;
$ ./semaphore.sh ACKNOWLEDGE;
$ ./semaphore.sh CORRECT;
$ ./semaphore.sh CANCEL;
Future improvements
ASCII Art - If someone wants to create nicer ASCII art, send a pull request or just open an issue with a sample. The framework is there and as little as possible is hardcoded, making it easy to add any design you want.
Quality Check - I have never actually learned semaphore, everything in this library was created based on Wikipedia. I need someone proficient in flag semaphore to error-check the output, and make sure the usage is correct.