Mini LaTeX Tutorial

This tutorial walks you through:

  1. Compiling a LaTeX document.
  2. Dealing with compiler errors.
  3. Mathematical formulas.
  4. Formatting code.

This tutorial assumes that you already have LaTeX installed on your machine. If you don’t, you need to install it. See here. By the way, UNIX lab machines already have LaTeX installed. Several students also report to me that Overleaf is pleasant to use, but I have not tried it myself.

Compiling a LaTeX document

Suppose you have a LaTeX file called “file.tex”. You can compile “file.tex” to a PDF like so:

Reepicheep:~ dbarowy$ pdflatex file.tex

pdflatex will print out a lot of stuff. If your “file.tex” has no errors, you should see output that looks something like the following near the end,

Output written on file.pdf (1 page, 27256 bytes).

and you will have a PDF version of your LaTeX document.

Dealing with compiler errors

If things go wrong, you will need to debug your LaTeX, just as you debug any other computer program. Look for missing brackets (e.g., [ and ]) or curly braces (e.g., { or }), look for typos in commands, and above all, read the output that the compiler is printing. LaTeX error messages are not the most understandable things, but they usually do tell you where to find the error.

One important thing to be aware of is that the LaTeX compiler usually drops you into an interactive shell instead of just stopping (like javac does). For example,

Reepicheep:~ dbarowy$ pdflatex file.tex
 ... lots of output ...
! Undefined control sequence.
<recently read> \tod 
l.19   \item \tod

Annoyingly, your cursor sits on this line and doesn’t give you even a clue as to what to do. By the way, I used LaTeX for years without actually knowing the correct way to escape from this situation (I am not ashamed to admit that I actually used the kill command from another terminal). The correct thing to do is easy: type a capital X and press the ENTER key.

More importantly, this compiler message actually tells me where to find the problem. On line 19 (l.19), something about the LaTeX commands \item \tod causes an Undefined control sequence. One could argue that this is one of the worst ways to construct an error message, but hey, it’s all there.

When I open up my file.tex I see this on line 19:

  \item \tod{ANSWER}

Oops! \tod should be \todo. After fixing this and running pdflatex again, “file.tex” again compiles correctly.

Mathematical formulas

One of LaTeX’s great strengths is that it can produce beautiful-looking mathematical formulae. This is mostly easy to do, too: just put a mathematical expression in between a pair of dollar signs. For example:

$x + 5$

will produce a pretty-looking x + 5 expression.

I have not yet come across a mathematical figure that I could not reproduce using LaTeX. That’s not to say that it is always easy, just that it is possible. See the LaTeX/Mathematics reference for more information.

Formatting code

Code is sometimes frustrating to format in LaTeX. Fortunately, there are two approaches, one easy, and one… less easy. Let’s look at the easy one first.

LaTeX has many special “environments” that you can use for specially-formatted blocks of text. A very useful one for code is called verbatim. You use it like this:

  code goes here

For example,

  public static void main(String[] args) {
    System.out.println("Hello world!");

verbatim will reproduce the text using a monospaced “typewriter” font that looks a lot like how we normally format code.

But LaTeX actually lets you do some very fancy things with code. Instead of using the verbatim environment, you can alternatively use the lstlisting environment. You need to do a little extra work:

  1. You must add \usepackage{listings} to the top of your document.
  2. You must supply a \lstset command, e.g., \lstset{language=Pascal} for the Pascal language.
  3. You can then put your code inside a lstlisting environment.

The listings package can produce genuinely beautiful looking formatted code, with syntax highlighting and everything. If you’re interested, see the LaTeX/Source Code Listings page.