param=${param:-$(read -p "Enter parameter: "; echo "$REPLY")}

Enter parameter if empty (script becomes interactive when parameters are missing)

Can be used for command line parameters too. If you have a more complicated way of entering values (validation, GUI, ...), then write a function i.e. EnterValue() that echoes the value and then you can write: param=${param:-$(EnterValue)}

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What do you think?

Any thoughts on this command? Does it work on your machine? Can you do the same thing with only 14 characters?

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