I consider myself reasonably proficient in the shell, but I learned something just from your sample pages (process substitution). Purchased!

If you have not skimmed through the manual of bash¹ enough to learn about process substitutions, what makes you think you would read a book?

1. <https://www.gnu.org/software/bash/manual/bash.html>

Different people prefer different formats for information. Some people prefer to read the manual from start to finish while others learn better seeing the same concepts in a hands-on tutorial.

From reading the sample of OP's book, it seems far more practical and accessible than the bash manual, so I'm not surprised that a lot of people would read OP's book that have no interest in reading the bash manual cover to cover.

Maybe because they didn't think to?

Because generally a manual is “here is every single detail of this thing”, while a book like this is “here’s an overview of the particularly useful stuff.”

I’ll go to the manual if I’m trying to understand how a particular thing works, or how to do a particular thing, but it’s not as useful to me for feature discovery.

Thanks!

Hmm, the example page doesn't convince me, for example

> The diff utility can compare files and print their differences. If we pass it the result of ls commands, we can compare the contents of directories.

No, if you pass the output of ls commands, you might get an error because you'll pass a bunch of files to diff.

And last but not least there's

    diff -r directory-a directory-b

to compare two directories file by file.

I wanted to demonstrate the use of the substitution, not the best way to diff directories. Often I tried to create examples that demonstrate multiple concepts or tools at once to save space. But I see your point.

I think it was about demonstrating process substitution. You don't pass a bunch of files to diff, you pass the output of ls, as a file, to diff.

I actually thought it was awesome to see that. I use this a lot to diff the output of commands and many people don't know about it.

Page 12 of the example pdf ends with "On Linux, the PATH looks something like this:", but then there's no PATH example shown.

Page 13 isn't in the example pdf. It's a bunch of scattered pages to give you a feel for the whole thing.

Yes, the linked sample pages are just randomly taken pages from the book PDF, as I put it together quickly for the Show HN. Apologies. I will make a better example when I rework the landing page.

if you add a cover page with http link, an example download read at a later time will find its way back more easily. Looks good!

Thanks for the suggestions:)