Echo ENV
This script gathers the CGI environment variables and prints them to
the screen. In Perl, the CGI environment variables are stored in a special
hash called %ENV. The script uses a loop to print each element of %ENV.
Most scripts, which use environment variables, only use one or two at
a time.
Open a text editor to write the script:
pico echoenv.cgi
Type the following Perl code in your text editor exactly as it appears
here:
#!/usr/local/bin/perl
print "Content-type:text/html\n\n";
print '<HTML><HEAD><TITLE>echoenv.cgi results</TITLE></HEAD>';
print '<BODY BGCOLOR="FF0066">';
foreach $i (keys %ENV) {
print "<B>$i</B> = $ENV{$i}<BR>";
}
print '</BODY></HTML>';
Save the file and exit the editor.
Make the script executable, type:
chmod 755 $HOME/public_html/cgi-bin/echoenv.cgi
This table includes a line-by-line explanation of echoenv.cgi:
| #!/usr/local/bin/perl |
Tells the server the Perl interpreter is located in the directory
/usr/local/bin/perl |
print "Content-type:text/html\n\n";
|
Is a print statement for the HTTP
header. In this case, the header tells the Web browser to display
HTML formatted text. |
print '<HTML><HEAD><TITLE>echoenv.cgi
results</TITLE></HEAD>';
print '<BODY BGCOLOR="FF0066">'; |
These print statements start the HTML document, create the <HEAD>
section, and begin the <BODY> section of the HTML page. |
foreach $i (keys %ENV) {
print "<B>$i</B>
= $ENV{$i}<BR>";
} |
This foreach loop prints the key/value pairs of the %ENV
hash. |
| print '</BODY></HTML>'; |
This print statement closes the HTML document. |
| 
