## PowerShell, 24 Bytes

    param($a)do{$a}while($a)

Gets variable `$a`, then uses the `do-while` loop functionality to output `$a` at least once, but continuing the loop if `$a` is truthy (i.e., `1`).


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Alternatively, using traditional while looping, also 24 bytes

    param($a)while($a){$a}$a

In this instance, if `$a` is falsey, the `while` loop will never be executed and just the value of `$a` will be printed in the end statement. If `$a` is truthy, the program will enter the `while` loop and continuously print the value of `$a`.