Perl Programming Fundamentals

In Perl regular expressions, a quantifier specifies how many times the preceding character, group, or character class should match. Common quantifiers include * (0 or more), + (1 or more), ? (0 or 1), and {n,m} (between n and m times). Character classes match sets of characters, metacharacters have special meanings, and assertions are zero-width matches.

In Perl, single quotes do NOT interpolate variables - the string is taken literally. Double quotes would replace $prize with its value, but single quotes print '$prize' as-is. This is a key difference between single and double quoted strings in Perl.

In Perl documentation and community usage, the terms 'function' and 'subroutine' (often shortened to 'sub') are used interchangeably to describe a named block of code that performs a specific task. While some languages distinguish between them based on return values, Perl does not.

Perl provides three standard file handles: STDIN (standard input), STDOUT (standard output), and STDERR (standard error). These are built-in file handles available in every Perl program for input/output operations. Both stdin and stdout are valid Perl file handles, making option E correct.

The -w switch in Perl enables warnings, alerting you to potential issues including typos, uninitialized variables, and other problems in your script. This is a best practice for Perl development to catch errors early. The -W capital version enables ALL warnings regardless of scope.

The Perl stat function returns a 13-element list containing file statistics. These include the device ID, inode number (E), mode, number of links, UID, GID, rdev, size, atime (C - last access), mtime, ctime, blksize, and blocks. Since both C and E are part of the array, 'C&E' is correct.

CGI (Common Gateway Interface) is NOT a programming language - it's a protocol or standard for web servers to execute external programs and generate dynamic web content. CGI programs can be written in Perl, Python, C, or any other language that the server supports. The interface itself is language-agnostic.

In Perl, scalar variables (holding single values like strings or numbers) always begin with the $ sign. This sigil indicates a scalar variable. Arrays use @, hashes use %, and subroutines use &. The $ prefix makes it easy to identify scalar variables in code.