Perl Interview Questions Part 1

Q:Why do you use Perl?

A:Perl is a powerful free interpreter.Perl is portable, flexible and easy to learn.

Q:How do I set environment variables in Perl programs?

A:you can just do something like this:

$path = $ENV{'PATH'};

As you may remember, "%ENV" is a special hash in Perl that contains the value of all your environment variables.

Because %ENV is a hash, you can set environment variables just as you'd set the value of any Perl hash variable. Here's how you can set your PATH variable to make sure the following four directories are in your path::

$ENV{'PATH'} = '/bin:/usr/bin:/usr/local/bin:/home/yourname/bin';

Q:Which of these is a difference between C++ and Perl?

A:Perl can have objects whose data cannot be accessed outside its class, but C++ cannot.

Perl can use closures with unreachable private data as objects, and C++ doesn't support closures. Furthermore, C++ does support pointer arithmetic via `int *ip = (int*)&object', allowing you do look all over the object. Perl doesn't have pointer arithmetic. It also doesn't allow `#define private public' to change access rights to foreign objects. On the other hand, once you start poking around in /dev/mem, no one is safe.

Q: :How do I do fill_in_the_blank for each file in a directory?

A:Answer:Here's code that just prints a listing of every file in the current directory:

#!/usr/bin/perl -w

opendir(DIR, ".");

@files = readdir(DIR);

closedir(DIR);

foreach $file (@files) {

print "$file\n";

}

Q:How do I generate a list of all .html files in a directory?

A:Here's a snippet of code that just prints a listing of every file in the current directory that ends with the extension .html:

#!/usr/bin/perl -w

opendir(DIR, ".");

@files = grep(/\.html$/,readdir(DIR));

closedir(DIR);

foreach $file (@files) {

print "$file\n";

}