Every Perl program must be passed through the Perl interpreter in order to execute. The first line in many Perl programs is something like:
The interpreter compiles the program internally into a parse tree. Any words, spaces, or marks after a pound symbol will be ignored by the program interpreter. After converting into parse tree, interpreter executes it immediately. Perl is commonly known as an interpreted language, is not strictly true. Since the interpreter actually does convert the program into byte code before executing it, it is sometimes called an interpreter/compiler. Although the compiled form is not stored as a file.