Obscure string in bash script

Question

I am trying to do the following:

obscure ( ) {
    local txt="$1"
    echo "$txt" | tr '[:alnum:]' '*'
}

So that if I do:

obscure 'mysecretstring'

I get:

**************

What matcher can I use for tr, instead of [:alnum:] to mean 'any character'?

Is there a better way to implement obscure? Another option that comes to mind is sed.

Answer 1

You can use pure BASH:

obscure() {
   local txt="$1"
   echo "${txt//?/*}"
}

"${txt//?/*}" will replace each character in $txt by *

Test it:

obscure 'mysecretstring3123213213'
************************

obscure mysecretstring
**************

obscure '!@#$%^&*()_+=-'
**************

obscure '中文版'
***