According to TeXbook TeX does preprocess files of .tex-input line per line (converting all characters of the line to TeX's internal character-representation-scheme (ASCII or Unicode), truncating sequences of space-characters at ends of lines, appending a character specified by
So questions arise:
- What is the maximum amount of characters per line in .tex-input files?
- How does TeX behave when encountering at reading-time a line that is too long?
You can use TeX for writing external text files.
- How does TeX behave when attempting to write a line to external text file that is too long/that has more characters than TeX can place into a single line of an external text file?
\write-primitive always writes an entire line to external text-file.
- Are there means for
- just beginning a new line of an external text-file?
- appending characters to the current line of an external text-file?