Let’s imagine you have a laptop you share with a friend for project work. They’re not million-dollar secrets you’re keeping, but on the other hand, you don’t want just anyone reading those files. At the same time, your friend is very forgetful, likely not to remember a typical password.<\/p>\n
To accommodate your friend, while keeping out the casual snoops, you settle on a three-character password with a variable middle character. Let’s imagine the password is n[any character]n<\/span>. Then, nan<\/span> or n@n<\/span> will succeed, but nano<\/span> won’t (too long). Of course, the first and third characters must both be n.<\/p>\n Pattern matching is done using regular expressions, or regex.<\/p>\n Here is the Perl code that can accept the entry, then decide if it matches: I’ll be explaining some nuts and bolts of the regex line in a coming post:)<\/p>\n Source:<\/p>\n McGrath, Mike. Perl in easy steps<\/u>. Southam: Computer Step, 2004.<\/p>\n Robert’s Perl tutorial<\/a><\/p>\n
\n
\nprint “Enter your password, please.\\n\\n”;
\n
\n$word=<STDIN>;
\n
\nif ($word=~\/^n.n$\/){ #the regex line<\/span>
\nprint “Correct.\\n”;
\n}
\n
\nelse{
\nprint “Incorrect password; access denied.\\n”;
\n}<\/span><\/p>\n