perl function sethostent

The sethostent function in Perl is used to rewind the hosts file (/etc/hosts) and start reading from the beginning. Here's an example of using sethostent in a script to read all the hosts from the hosts file:

while (my ($name, $aliases, $addrtype, $length, @addrs) = gethostent()) {
    print "Host name: $name\n";
    print "Host aliases: ", join(',', @$aliases), "\n";
    print "Address type: $addrtype\n";
    print "Address length: $length\n";
    print "Addresses: ", join(',', @addrs), "\n";
}

# rewind the hosts file and start again
sethostent();

# read the hosts again
while (my ($name, $aliases, $addrtype, $length, @addrs) = gethostent()) {
    print "Host name: $name\n";
    print "Host aliases: ", join(',', @$aliases), "\n";
    print "Address type: $addrtype\n";
    print "Address length: $length\n";
    print "Addresses: ", join(',', @addrs), "\n";
}

In this example, the gethostent function is used to read each host entry from the hosts file in turn, and the details of each host are printed using print statements.

After reading all the hosts from the hosts file, the sethostent function is called to rewind the file pointer to the beginning of the file. This is necessary if we want to read the hosts again from the beginning.

Finally, the gethostent function is called again in a loop to read each host entry from the beginning of the hosts file, and the details of each host are printed again.

Note that the sethostent function is not necessary if you only need to read the hosts file once, as the file pointer is automatically rewound to the beginning of the file when the end of the file is reached.