. Write a shell script to print the file names of all files having .txt extension of a given directory after converting to uppercase letters. The input (directory name) should be given as command line argument. The script will also check whether sufficient arguments are passed or not and whether the argument is a directory or not. In case of invalid input, proper message should be displayed.

What have you tried so far? This is pretty straightforward and we will not do your homework for you.

Topics to look into: ${#} : Number of command line arguments tr : Translate between sets of characters ls : Directory listing echo : Printing to output device -d : File test for directory

You will want to look at the man pages for any of them. To learn about man just type man man on the command line.