The transform command is similar to the Linux tr command. The characters are translated according to the character sequence given. For example, y/ABC/abc/ will convert lowercase abc into uppercase ABC.
Here is an example:
$ cat shopping.txt
The output will be:
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 $ sed '2,4y/abcdefghijklmnopqrstuvwxyz/ABCDEFGHIJKLMNOPQRS TUVWXYZ/' shopping.txt
The output will be:
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
In this example, for lines 2, 3, and 4, all the lowercase letters are converted to uppercase letters.