Is anybody aware of the usage of vienna-rna package? I am trying to use a utility provided by the package to convert .ct structure format of RNA secondary structure into vienna dot bracket format but i am unable to use it. i type the command as given by the tutorial i.e.

ct2b.pl filename.ct > output.struct

but it gives me the error command not found

I have also tried

perl ct2b.pl filename.ct > output.struct

and

perldoc ct2b.pl filename.ct > output.struct

but it still gives the error. can somebody help?