Scripting in general...

Concept of "the shell"

What are some of the things you can do

Commonly used tools in shell scripts
	sed - Stream EDitor
	awk/gawk - pattern scanning and processing language 
	tr - translate or delete characters
	dc - arbitrary precision calculator
        bc - arbitrary precision calculator language
	grep/egrep/fgrep/rgrep
       

Languages we might use...
   bash/sh
   perl

advantages
disadvantages

shell scripts
-----------
When not to use shell scripts

     * Resource-intensive tasks, especially where speed is a factor
       (sorting, hashing, etc.)
     * Procedures involving heavy-duty math operations, especially
       floating point arithmetic, arbitrary precision calculations, or
       complex numbers (use C++ or FORTRAN instead)
     * Cross-platform portability required (use C or Java instead)
     * Complex applications, where structured programming is a necessity
       (need type-checking of variables, function prototypes, etc.)
     * Mission-critical applications upon which you are betting the ranch,
       or the future of the company
     * Situations where security is important, where you need to guarantee
       the integrity of your system and protect against intrusion,
       cracking, and vandalism
     * Project consists of subcomponents with interlocking dependencies
     * Extensive file operations required (Bash is limited to serial file
       access, and that only in a particularly clumsy and inefficient
       line-by-line fashion)
     * Need native support for multi-dimensional arrays
     * Need data structures, such as linked lists or trees
     * Need to generate or manipulate graphics or GUIs
     * Need direct access to system hardware
     * Need port or socket I/O
     * Need to use libraries or interface with legacy code
     * Proprietary, closed-source applications (shell scripts put the
       source code right out in the open for all the world to see)


Perl
----

* Encourages lazy or non-optimal code
* Not as efficient as a compiled language
* Weak typing
* Hard to read and maintain code
* Lack of authoring tools