Some commands of `bitcoin-tx` accept an index of an existing input/output, e.g. `delin` or `delout`.  And while the index is checked for being out-of-bounds, garbage (non-numeral characters) are happily accepted.  All of the following are fine:

    $ bitcoin-tx -create outaddr=1:1M72Sfpbz1BPpXFHz9m3CdqATR44Jvaydd delout=
    $ bitcoin-tx -create outaddr=1:1M72Sfpbz1BPpXFHz9m3CdqATR44Jvaydd delout=foobar
    $ bitcoin-tx -create outaddr=1:1M72Sfpbz1BPpXFHz9m3CdqATR44Jvaydd delout=0bla

I think all of them should throw an error instead of silently treating the index as zero.

The reason for this is that internally, `atoi` is called - and that by design discards anything after the first non-numeric character (and may just return zero if there are no numerals at all).

A possible fix would be to use `strtol` instead and to verify that the returned `endptr` is actually the end of the input string.  Alternatively, one could convert the integer back to a string and require that it matches the input string exactly.
for(int pos = 1; pos <= int(numkeys); pos++) {
        CPubKey pubkey(ParseHex(vStrInputParts[pos + 2]));
        if (!pubkey.IsFullyValid())
            throw std::runtime_error("invalid TX output pubkey");
        pubkeys.push_back(pubkey);
    }
    
    bool bSegWit = false;
    bool bScriptHash = false;
    if (vStrInputParts.size() == numkeys + 4) {
        std::string flags = vStrInputParts.back();
        bSegWit = (flags.find('W') != std::string::npos);
        bScriptHash = (flags.find('S') != std::string::npos);
    }
    else if (vStrInputParts.size() > numkeys + 4) {
        
        throw std::runtime_error("Too many parameters");
    }
    CScript scriptPubKey = GetScriptForMultisig(required, pubkeys);
    if (bSegWit) {
        for (CPubKey& pubkey : pubkeys) {
            if (!pubkey.IsCompressed()) {
                throw std::runtime_error("Uncompressed pubkeys are not useable for SegWit outputs");
            }
        }
        
        scriptPubKey = GetScriptForWitness(scriptPubKey);
    }
    if (bScriptHash) {
        if (scriptPubKey.size() > MAX_SCRIPT_ELEMENT_SIZE) {