The c command is the change command. It allows sed to modify or change existing text with new text. The old text is overwritten with the new:
$ cat shopping.txt
The output is as follows:
Product Quantity Unit_Price Total_Cost Apple 2 3 6 Orange 2 .8 1.6 Papaya 2 1.5 3 Chicken 3 5 15 Cashew 1 10 10
Here is an example:
$ sed '/Papaya/c Papaya is out of stock today !' shopping.txt
The output is as follows:
Product Quantity Unit_Price Total_Cost Apple 2 3 6 Orange 2 .8 1.6 Papaya is out of stock today ! Chicken 3 5 15 Cashew 1 10 10
In this example, the line containing the expression Papaya is changed to the new line, Papaya is out of stock today!.