Perl Cookbook freely available here
Tom Christiansen and Nathan Torkington
Many programming languages force you to work at an uncomfortably low level. You think in lines, but your language wants you to deal with pointers. You think in strings, but it wants you to deal with bytes. Such a language can drive you to distraction. Don’t despair; Perl isn’t a low-level language, so lines and strings are easy to handle.
Perl was designed for easy but powerful text manipulation. In fact, Perl can manipulate text in so many ways that they can’t all be described in one chapter. Check out other chapters for recipes on text processing. In particular, see Chapters 6 and 8, which discuss interesting techniques not covered here.
Perl’s fundamental unit for working with data is the scalar, that is, single values stored in single (scalar) variables. Scalar variables hold strings, numbers, and references. Array and hash variables hold lists or associations of scalars, respectively. References are used for referring to values indirectly, not unlike pointers in low-level languages.
Numbers are usually stored in your machine’s double-precision floating point notation. Strings in Perl may be of any length, within the limits of your machine’s virtual memory, and can hold any arbitrary data you care to put there— even binary data containing null bytes.
A string in Perl is not an array of characters—nor of bytes, for that matter. You cannot use array subscripting on a string to address one of its characters; use substr for that. Like all data types in Perl, strings grow on demand. Space is reclaimed by Perl’s garbage collection system when no longer used, typically when the variables have gone out of scope or when the expression in which they were used has been evaluated.
In other words, memory management is already taken care of, so you don’t have to worry about it.
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