CTP208 Exercises

Perl Exercises

Write a Perl program to input one line from the standard input (keyboard), with multiple words in it, and print these words on separate lines to the standard output (terminal).
Eg. If the user types in "A computer without a Windows opsys is like a cake without mustard.", your program should produce the lines
```
A
computer
without
a 
Windows
opsys
is
like
a
cake
without
mustard.
```
Write a Perl program that asks a user for a filename, then open that file and replace all "A"s with "Q"s and "a"s with "q"s. Then write the changes back to the file.
Write a Perl program that looks through /etc/passwd file (on smb.ctp), for names that occur in more than one person's full name and prints the full names of those people. For example the name "Ali" appears in full names of 4 people and the name "Can" occurs in names of 2 people. For example your program should find "Ali"
Hint: after splitting the line, create an associative array with the names as the keys and the number of times it was seen for the value. Now you can look for the associative array entries with a value greater than 1.
An example output should look like:
```
The name "Ali" occurs 4 times:
       Mehmet Ali Karajadasdk
       Ali sadasdasda
       Ali jhgsdjga
       Ali Kemal sdfads
       
The name "Can " occurs 2 times:
       Can Ugur Ayfer 
       Can Temel
       
```

Regular Expression Exercises

Note that you can test your regular expressions using the RegExp Tester linked on the CTP208 page.

Write a Perl Regular expression to test whether a string looks like a valid IP address.
Write a Perl program to input a file of "Name Surname" lines and produce a second file with lines in format "Surname, Name" (note the comma after the surname). YOU MUST USER REGULAR EXPRESSIONS TO IMPLEMENT THE PROGRAM.
Write a Perl program to eliminate the blank lines from a text file. eg: If the source file has the lines
```
Line 1
Line 2

Line 4

Line 6
```
Your program should modify this file to become
```
Line 1
Line 2
Line 4
Line 5
Line 6
```

Perl CGI Exercises

Write a Perl CGI application which will display "non-Bilkent hit statistics" for the website smb.ctp.bilkent.edu.tr. You can find the Apache web server access logs in the file /usr/local/apache/logs/access_log on the smb.ctp.bilkent.edu.tr host. Please note that your program should generate a report page like

Foreign visitor statistics for smb.ctp.bilkent.edu.tr
12 Sep 2002 - 13:34

IP Number No. of Hits

123.234.23.12 12

23.53.3.121 63

45.43.2.65 43

etc etc

Write a Perl CGI application which will prompt the user for a word (any word) and search the Electronic Journals database and display names, subjects and publishers of all journals which contain this word in their subjects.

The Electronic Journals database is located on host : lists.bilkent.edu.tr
The table which contain journal records is called "ejournals"
A user who has only "SELECT" access to this database is named "demo"
The password for this user is "demo"
The output of the "describe ejournals;" MySQL command is

mysql> describe ejournals;
+-------------------+------------------+------+-----+---------+----------------+
| Field             | Type             | Null | Key | Default | Extra          |
+-------------------+------------------+------+-----+---------+----------------+
| title             | char(255)        | YES  |     | NULL    |                |
| publisher         | char(100)        | YES  |     | NULL    |                |
| url               | char(255)        | YES  |     | NULL    |                |
| e_issn            | char(50)         | YES  |     | NULL    |                |
| print_copy_exists | char(5)          | YES  |     | NULL    |                |
| print_issn        | char(50)         | YES  |     | NULL    |                |
| bliss_url         | char(255)        | YES  |     | NULL    |                |
| subject           | char(50)         | YES  |     | NULL    |                |
| note              | char(200)        | YES  |     | NULL    |                |
| ipcheck_url       | char(255)        | YES  |     | NULL    |                |
| password          | char(50)         | YES  |     | NULL    |                |
| login             | char(50)         | YES  |     | NULL    |                |
| s_date            | char(10)         | YES  |     | NULL    |                |
| e_date            | char(10)         | YES  |     | NULL    |                |
| vendor            | char(100)        | YES  |     | NULL    |                |
| id                | int(10) unsigned |      | PRI | 0       | auto_increment |
| group_id          | int(11)          | YES  |     | NULL    |                |
+-------------------+------------------+------+-----+---------+----------------+
17 rows in set (0.01 sec)

PHP Exercises

Write a PHP application which will do exactly the same thing as the Perl CGI problem described above.