So at this point, the quotes have been removed by CircleCI’s internal processing. You can override this by adding escaped quotes to the parameter value so your input string goes from
"304939220200" -> "/"304939220200/""
But this looks like a complete mess and while the echo command will show the expected output the shell is likely to then remove the quotes as it processes the command. This in turn can be fixed by placing single quotes around the variable so the echo now looks like
With all these changes being made to the data input your best option is likely to write some additional shell script to check which parameters are being passed and then add the quotes if needed.