To have a full-blown Bitcoin client in shell scripting might be a bit difficult especially with the cryptographic aspect required (except if everything could be called from command line using OpenSSL...) but nothing is impossible.
Is it possible to use ECDSA with openssl ? I've looked for this in the openssl manual page, but I haven't found anything apart from DSA and RSA. Anyway indeed most of the parts of the program would be called with command line programs, especially cryptographic stuffs.
(PS. you don't have to put a whole pipe in a same line. The '|' character can end a line.)