MySQL

MySQL is a language (or set of tools) that interacts with a relational database.

SQL is Structured Query Language

The way it works:

You create a database with N columns (of any type) -- imagine a listing of people in this room, their heights, their ages, and whether they are left- or right-handed

You can then query on the database like this:

%> SELECT name FROM table_name WHERE name LIKE 'trill'

You can do lots of complicated things here. You can update certain values

%> SET handedness = 'left' WHERE name = 'trilling'

MySQL is used a lot for web stuff, for database administration, and for many different kinds of science applications.

Naturally, Perl and Python (and PHP, Java) interact with MySQL with a lot of canned routines.

Check out Wikipedia and mysqltutorial.org.

Shell scripting

Shell scripting is kind of a catch-all term for putting a series of commands into a single executable file.

An example.

How do we use this file?

%> chmod +x example1.sh -- first make it executable

%> ./example1.sh -- then simply execute it

You can use variables in shell scripts too.

Another example.

%> chmod +x example2.sh -- make it executable

%> ./example2.sh trilling -- did it work?

There are lots and lots and LOTS of other things you can do with shell scripts.

For example, you can do loops, conditional statements, math, and so on.

And of course, you can have shell scripts call other shell scripts, etc.

Here's a good reference.