$ Sign

I believe there were originally three lines but one was taken out by the Tax Office. Over time, bracket creep meant they got another one. Soon you will only get the S.

I was working in a bank when decimal currency was introduced, I stopped using the second line about 9.15am on 14/2/66

Probably not worth worrying about the number of lines in a dollar sign, if a certain party get hold of Australia you won't have as many $$$$'s with or without lines. The S will simply stand for something different, S for _ _ _ _ _ _ ism.

Interestingly, the only country in the world where 2 strokes through the dollar sign is the official symbol - is America.
But Americans can utilise either a double or single stroke in regular use, and it is accepted.

All other countries utilise a single stroke - apart from Australia, which uses a single or a double stroke, according to which typing device, keyboard, programme or font you are using.

Both styles of symbol are acceptable here, officially and unofficially.

Cheers, Ron.

My personal take on this is because in the fonts we use on computers the $ sign only has one (line).

Following your query I went to my DTP program and typed a dollar sing for all the fonts and each one came out with just one line/stroke.

So I will blame Steve Jobs and Bill Gates at this stage. I have no idea if this theory is correct, but it strikes a chord with me.

OBJ

In recent times its probably just evolved that way because of how much detail you can put into a typewriter type head and still maintain clarity when using a ribbon. An S with two II through it would be a poorly defined blob, so it was down to one vertical line as it still got the point across.

and its easier to write.

Someone has put a bit of thought into the question:

https://en.wikipedia.org/wiki/Dollar_sign

Its all to do with the keyboard on the computer ...

Thanks everyone for your answers, they are really appreciated.

The original $ sign was actually U&S overlaid with each other denoting US DOLLAR.
The US dropped the “loop” to just “II” & S overlaid in the early 1900s
As stated elsewhere here the computer key board simplified it to just “$”.