DB<106> sprintf '%03o%03o', ord("\r"),ord("\n")
 => "015012"
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if you need to convert a whole string, consider

  DB<104> map { sprintf '%03o', ord($_) } split //, "a \r\n" 
 => (141, "040", "015", "012")
[download]

update

improved null padding, that is %03o instead of 0%o in sprintf.

the latter would produce:

  DB<109> sprintf '0%o', ord("a")
 => "0141"
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