Sending commands normally through serial monitor, but in void loop instead.

I have a device that takes commands through the serial monitor.

I have set it to send the 'r' command continuously by setting computerdata[0] = 'r'

I want to send commands that are more than one letter like "status". but every combination and variable I tried does not work.

I also wanted to do

char* = "stringvariable";
computerdata[0] = stringvariabl;e //but this doesn't work either.

char computerdata[20];

void loop(){
computerdata[0] = 'r';
rtd();
}

void ezoec(){
if (millis() - ecTimer >= 1000){ //start rtd timer
if (readec2 == 1){
computerdataec[0] = tolower(computerdataec[0]); //we make sure the first char in the string is lower case
if (computerdataec[0] == 'c' || computerdataec[0] == 'r')timeec = 1000; //if a command has been sent to calibrate or take a reading we wait 2000ms so that the circuit has enough time to take the reading.
else timeec = 300;

readec = 1;
readec2 = 0;
ecTimer2 = millis();
}
}
if (millis() - ecTimer2 >= timeec){
if (readec == 1){

// Serial.println("requestion ec data"); //print the data for ddebug
Wire.requestFrom(addressec, 48, 1); //call the circuit and request 48 bytes (this is more than we need)
codeec=Wire.read(); //the first byte is the response code, we read this separately.
while(Wire.available()){ //are there bytes to receive.
in_charec = Wire.read(); //receive a byte.
ec_data[iec]= in_charec; //load this byte into our array.
iec+=1; //incur the counter for the array element.
if(in_charec==0){ //if we see that we have been sent a null command.
iec=0; //reset the counter i to 0.
Wire.endTransmission(); //end the I2C data transmission.
break; //exit the while loop.
}
}
// Serial.println(ec_data); //print the data.
Wire.endTransmission(); //end the I2C data transmission.
readec2 = 1;
readec = 0;
ecTimer = millis(); // reset timer
ecTimer2 = millis();
}
}
}

To compare strings you have to use the strcmp function. They don't compare with the == operator.

Go have a look at the Serial Input Basics thread. Once you've gone through that you should have a better understanding.

You also need to understand what fits in a char variable is just one character. You can't cram a whole string in there.