Problem:
When trying to detect I2C devices on the Raspberry Pi (Raspbian) using i2cdetect, you see the following error:
$ i2cdetect bash: i2cdetect: command not found
Solution:
Install i2c-tools using
sudo apt -y install i2c-tools
After installing i2c-tools , you can use i2cdetect and other related tools such as i2cget.