Exercises

13.9 Exercises

The programs here are potentially dangerous! Be careful to test them in a mostly empty directory to make it difficult to accidentally delete something useful.

See Section A.12 for answers to the following exercises.

1.       [6] Write a program that works like rm, deleting any files named on the command line. (You don't need to handle any of the options of rm.)

2.       [10] Write a program that works like mv, renaming the first command-line argument to the second command-line argument. (You don't need to handle any of the options of mv or additional arguments.) Remember to allow for the destination to be a directory; if it is, use the same original basename in the new directory.

3.       [7] If your operating system supports it, write a program that works like ln, making a hard link from the first command-line argument to the second. (You don't need to handle options of ln or more arguments.) If your system doesn't have hard links, just print out a message telling what operation you would perform if it were available. Hint: This program has something in common with the previous one recognizing that could save you time in coding.

4.       [7] If your operating system supports it, fix up the program from the previous exercise to allow an optional -s switch before the other arguments to indicate that you want to make a soft link instead of a hard link. (Even if you don't have hard links, see whether you can at least make soft links with this program.)

5.       [7] If your operating system supports it, write a program to find any symbolic links in the current directory and print out their values (like ls -l would: name -> value).