Latex guide

Latex guide

What is latex, and why use it?

Latex is a coding language for formatting text into a typeset document, such as a PDF. It is used widely in scientific writing and publishing as a way of reusing a design template so that you as the writer can focus on content. I prefer writing in Latex because it allows me to use coding practices like git version control, commenting sections of text, and writing text in a fast and responsive text editor. Most importantly, it also makes working with bibtex citations super easy and convenient. Because latex works seamlessly with git and GitHub it helps me to stay organized by creating GitHub repositories for each manuscript, so that me and my collaborators can all work on a cloud-based document together.

Installing latex

My instructions below are for Ubuntu Linux, and will work in the Windows subsystem for Linux as well. If you are on MacOS I’m sure you can find similar installation instructions using google. In your linux bash terminal use apt to install latex with the following command, which may take a few minutes to install.

sudo apt install texlive-latex-extra

That’s it, you are now ready to make a .tex document and compile it with latex. In particular, we will use the program pdflatex to compile tex files into PDF documents.

Compile your first tex file.

Open any text editor and create a new file called hello-world.tex and write into it the text below and save the file.

Hello world 

This is a super simple tex document that includes the very minimum that is required to compile. The same tex commands are copied below but with additional notes for each section added by using the comment character (%). The ability to add comments to your tex files is a really important and powerful component to writing in latex. Commented lines are not compiled into the PDF. They can be left in the tex file as notes to yourself or collaborators, or to save earlier versions of a text while you are in the process of editing.

% This is a comment.

% The document class sets an overall style for the document 
% and is usually the first command in a tex file.

% additional add-on packages can be loaded here (see later examples)
% or additional styling options are added here, before beginning the doc.

% This command starts the document. Everything after this is intended to 
% be printed into the document (except comments). Everything
% before this involves loading styles and options that will be used in 
% this section to style text and images.

% This text is part of the document. This comment line however will 
% not appear in the document.
Hello world 

% This ends the document. Anything after this will be ignored.

You can now compile the tex document (using either one of the two tex files above since they are identical other than comments) by calling the command below from your bash terminal. Make sure to reference the full or relative path to the tex file that you just created. This will print some information to the terminal about what it is doing and any errors it encountered. The output is mostly mumbo jumbo. After it finishes use ls to look in your current directory. You should see a new hello-world.pdf file containing the typeset document. A few additional files will also be created which contain errors or auxiliary information such as citations. You can generally ignore those other files.

pdflatex hello-world.tex

Setup latex with your text editor (e.g., sublime)

Now that you’ve compiled a tex file from your bash terminal, you can move to a more advanced setup, which involves compiling the tex file directly from your text editor, thus avoiding the additional step of having to open a terminal. There are several options for this, including many dedicated latex editors/IDEs that are designed specifically to display a PDF next to your tex document (and online versions of this like overleaf). These can be nice, but I find them overall to be kind of clunky and ugly.

Instead I recommend learning to use latex in a powerful coding text editor such as sublimetext or vscode. This allows you to learn and use the same set of hotkeys and keystrokes to write text efficiently and maneuver around lines and paragraphs that you use when writing code.

For sublime text you can find instructions online for how to set it up for latex. For me, this involved adding a latex command to the build system to compile a .tex file when I press the F7 key. This makes it very easy to edit the .tex in my editor, press F7, and see the changes in the PDF document. This can also be setup on Windows as well, where latex is installed in your Linux subsystem, but Sublime is installed in Windows, instructions here.

Using comments

A benefit of using latex for writing large documents is that you can very easily comment out regions of the text that you wish to change, leaving behind a copy of the unedited version. I use this feature a lot when writing or editing. Unlike word or googledocs you don’t need to worry about whether your edits are easy to read over the previous version, and making lots of edits will not lag the system. I leave a copy of the unedited version in a comment until I’m satisfied it is no longer needed and then remove it.

Writing for version control

I recommend reading a simple latex tutorial to learn how the latex syntax works. For example, similar to markdown, line breaks are ignored in latex. This is a useful feature for interpreting your text like code. I always manually break paragraphs into lines that <=80 characters to avoid line wrapping when working in latex. This makes it so that when you push or pull changes with git the changes to each line will be highlighted and easy to find. If you write paragraphs as a single unbroken line that is wrapped by your editor then you will not be able to find changes in each version as easily.

Pushing changes to GitHub

Push changes to git frequently, especially when working with collaborators to avoid conflicts from arising when you both edit the same text. If conflicts do arise, use your text editor to go through one by one the regions between the >>> and <<< markers to select which version of the text you wish to keep. Then delete the delimiter markers.

Only commit and push the .tex file to git, not the PDF or auxiliary files. You and your collaborators can each compile the PDF anew when you load the changes to the .tex file. Git is great for versioning text-based documents like .tex but not PDFs. Add, commit and push new changes like below.

# pull in changes from your collaborators
git pull 

# example git commit to push changes to a manuscript
git add hello-world.tex
git commit -m "added genomics section to Methods"
git push