Apologies for any typos...
Thank you for these comments. I was half expecting to be slated... ;oD

I did check the auxiliary programs sleep and awk but could find nothing definite to tell me what was the current POSIX position for these.

I had lines similar to these:-

Code:

#!/bin/sh
text="1234567890"
char=$( cut -c2-6 <<< "$text" )
printf "%s" "${text:1:5}"
echo "$char"

Code:

$ shellcheck myscript
 
Line 3:
char=$( cut -c2-6 <<< "$text" )
                      ^-- SC2039: In POSIX sh, here-strings are undefined.
 
Line 4:
printf "%s" "${text:1:5}"
             ^-- SC2039: In POSIX sh, string indexing is undefined.

$ _

These really threw me and constant searching gave me the results inside the main code.
I could not find your "${platform%"${platform#??????}"}" anywhere, perhaps it was my search phrases but I spent hours trying to find non-time consuming methods without much success. Many thanks for those snippets.
I never even thought about using pettern matching, maybe because being an amateur I think differently to pros.

I was giong to use the "afplay", "aplay" and "/dev/dsp" as timers, (I will let you think about that one ;o) ), but decided against it as these are platform specific and would require some serious experimentation.

However I was aware of timings but that was not too important to me as learning POSIX requirements was; and guys like you supplying info helps others, (and judging by the posts on here, possibly tens of thousands of them), to steer through this quagmire too.

Again thanks, makes me feel good... ;o)

EDIT:
I forgot to add:- The rotating hourglass idea using ASCII - OUCH, but as you say a real challenge to draw at 45 degrees per movement... ;oO