Reference documentation, by its nature, can’t answer many of the important questions you might have during development:
Which tool is the most convenient to achieve what you want? It can be tempting to treat any Turing–complete language as a golden hammer when much more convenient alternatives exist.
What is the idiomatic way to achieve what you want? Developer communities will usually gravitate towards one way, or a small handful of ways of doing anything common, whether it’s how to indent code blocks or check whether a file is empty. Using these patterns makes it easier for others to understand your code, which is one of the most important characteristics of any software.
What are the important characteristics of this solution? Does it process one line (slow) or buffer (fast) at a time? Does it handle unusual input like newline, backslash, quotes, NUL, empty lines or non–existing paths? Is it robust in the face of third party failures?