One could see that as a different way of achieving what the parent poster said. You set a smaller goal that you can achieve (learn to do the task you need done right now) instead of the nebulous task of "learn the bash shell". They chose to read a book and gain everything in the book (regardless of whether they'd use it or not) and you chose to get something done.
In defense of their side of things, there will be important things in that book that they might never think to try to learn and that might not come up during internet searches for specific problems.
I tend to read books after I've tinkered with something for a couple of weeks, to fill in the blanks.
But what I actually wanted to point out is that learning bash doesn't seem to have a giant appeal to OP. If it had, he wouldn't put it off on a todo-list.
If you don't feel like to sit down and learn and entire topic for the fun of it, it's better to do it piece by piece.
In defense of their side of things, there will be important things in that book that they might never think to try to learn and that might not come up during internet searches for specific problems.
Both sides have merit, IMO.