pdftex:tldr:9dec3

The command pdftex -halt-on-error ${source-tex} is using the pdftex program to compile a TeX source file into a PDF document. Let's break down the components:

• pdftex: It is a command-line program for compiling TeX files into PDF documents. It is an extension of the original tex program but with additional features to handle PDF output directly.
• -halt-on-error: This flag tells pdftex to halt the compilation process if it encounters any errors while processing the TeX source file. By default, pdftex would continue compiling despite errors and produce an incomplete or incorrect PDF. With this flag, it immediately stops and displays the error message when an error occurs.
• ${source-tex}: This is a placeholder or variable that should be replaced with the actual filename and path of the TeX source file you want to compile. The ${source-tex} syntax suggests that it's using a shell variable or a placeholder for a variable that will be expanded to the actual value at runtime.

So, when you run the command pdftex -halt-on-error ${source-tex}, it invokes the pdftex executable, sets the -halt-on-error flag to ensure immediate stopping on errors, and then compiles the TeX source file specified by the ${source-tex} variable.