Exercises
See Appendix A for answers to the following exercises:
[6] Write a program that changes to some particular (hardcoded) directory, like the system’s root directory, and executes the
ls -l
command to get a long-format directory listing in that directory. (If you use a non-Unix system, use your own system’s command to get a detailed directory listing.)[10] Modify the previous program to send the output of the command to a file called
ls.out
in the current directory. The error output should go to a file calledls.err
. (You don’t need to do anything special about the fact that either of these files may end up being empty.)[8] Write a program to parse the output of the
date
command to determine the current day of the week. If the day of the week is a weekday, printget to work
; otherwise, printgo play
. The output of thedate
command begins withMon
on a Monday.[336] If you don’t have adate
command on your non-Unix system, make a fake program that prints a string similar to one thatdate
might print. We’ll give you this two-line program if you promise not to ask us how it works:#!/usr/bin/perl print localtime() . "\n";
[336] At least when the days of the week are being given in English. You might have to adjust accordingly if that’s not the case on your system.
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