In Arduino a built in LED is attached with number 13 Digital pin. Is there any LED like Arduino in Raspberry Pi,which I can use to test my code?
Unfortunately the Pi has no GPIO programmable built-in LED.
Instead, you'd have to make a simple circuit between two pins, e.g. pin 9 and 11 (https://pinout.xyz/), with an LED and resistor (around 100 ohms should be fine). You can then control the LED using the
gpio mode 11 out to enable output,
gpio write 11 1 to turn on the LED, and
gpio write 11 0 to turn off the LED.
More details are available at https://thepihut.com/blogs/raspberry-pi-tutorials/27968772-turning-on-an-led-with-your-raspberry-pis-gpio-pins.
Yes, it is possible to control the built-in leds. Green LED is easier.
According to here, though it is probably Pi 3 specific, since it didn't work for my Pi 4:
In the terminal:
sudo echo 1 > sudo /sys/class/leds/led0/brightness
This turns the green led on.
sudo echo 0 > sudo /sys/class/leds/led0/brightness
To turn off the activity indicator override: (put it back how it was)
echo mmc0 >/sys/class/leds/led0/trigger
though it is probably Pi 3 specific, since it didn't work for my Pi 4
It works on the 4 as well, you just need to set the right trigger. The instructions that you provided are not applicable to the 4 or just incorrect.
This will tell you what triggers you have available:
To enable manual control on a 4, do:
echo gpio |sudo tee /sys/class/leds/led0/trigger
Then control with:
# Any number > 0 will do echo 255 |sudo tee /sys/class/leds/led0/brightness # Zero turns it off echo 0 |sudo tee /sys/class/leds/led0/brightness