Well, I was not able to find the interval then. I think it's safer to get prompted by the mysql client for password, or maybe use a configuration file making sure its access is restricted

I'm grateful for this. However, I've been reading bash-beginners-guide and it's not the smoothest introduction. It's kind of an awkward combination of vague and precise details. E.g.:
That seems specific and yet totally uninformative at the same time.

The main problem I'm having is understanding the script syntax. E.g., when and why do we use quote marks and what's the point of all the double parens and square brackets and what's the role of the dollar sign, and why put a semicolon after the brackets in an if statement and how do the || and && operators effect control within the script, etc.


I may have to get the book. Kinda surprising that book is 560 pages!

Well I guess the general answer to question about vagueness is more of a subjective one as I find the portion you quoted completely understandable and succinct.

As for your syntax example, not only is not a single example but dozens and most of which boils down to a learning process, but to break it down a little for you:

when and why do we use quote marks :- when learning the answer is to always use double quotes unless you know why not to

what's the point of all the double parens and square brackets :- this would be a question of showing an example (which there are plenty in the pages listed), but the short list would be:

() - create a sub-shell
(()) - arithmetic operations
[] - [ itself is a bash command and is interchangeable with the 'test' command
[[]] - this is a more advanced version of the single square bracket, for example you can perform regular expressions

The above are not to be looked at as the definitive list of options either, but as said, you are to learn how and when to use each

what's the role of the dollar sign :- with a variable this is to identify you wan the variable to return its value

why put a semicolon after the brackets in an if statement :- if you read on you will find this is only needed when multiple commands are on the same line. in the case of the 'if' it will be if you place 'then' on the same line as the test

how do the || and && operators effect control within the script :- || = OR ... && = AND (at a basic level)


Again, please persist and read (re-read) constantly ... this is after all a new language you are learning

Like grail, I think the selection you posted stands on its own well enough. Although I admit that if you have limited prior familiarity with the Unix concepts of environment and process forking, the brief mention there may not stand out.

The shell is a special kind of environment in that it puts the many powerful Unix concepts and system services literally and interactively at your fingertips.

So some familiarity with those Unix/Linux basics will go a long way toward understanding how the shell is intended to work (and such familiarity is listed as a prerequisite in the guide).

That statement reminds me of a fortune, something about a helicopter pilot in Redmond... but I digress.

Try to not get bogged down, and if you can't figure something out, you know where to ask for help!

The syntax is different from many other languages, but still it is just another syntax.

To add to what grail has already said, and anticipate a few other questions...

The [ character is actually a command, the same as test, and not just a syntax element. To see this...

One consequence of this is that you must separate the enclosing brackets from the enclosed arguments with whitespace, just as you must separate the arguments of any other command from the command itself! (Actually bash uses a built-in version of [, but the behavior is the same).

The double square-bracket test syntax, [[...]] is an extended test notation introduced by ksh but now adopted by bash as well. It differs from the original test in that word and wildcard expansions are not performed, so quoting is less important. It also adds a list of test conditions not availale with the older test syntax, but it supports all of the older options so that you can always use [[...]], whatever test condition you are using.

Shell scripting has a few quirks, but it is well worth gaining some proficiency with it. Once you have gained basic familiarity it will become one of the most used and most powerful tools in your bag of tricks!

I think it is a very good book. It is tutorial in style, but also makes a very good reference. It includes a little of the history of common shells, and their differences as well.

And unlike many computer books, it is not likely to become outdated any time soon! The shell is a well established and slowly changing component at the core of Unix/Linux, so the book will remain relevant for a long time - money well spent.

Good luck!

Without belaboring the point too much, I have to disagree. Take this, for example:
Mightn't a bash script or single line in CLI may have many commands? In what sequence are these commands executed? What is the mechanism by which BASH makes this determination (cue the PATH concept here). What constitutes "normal" and "abnormal?" Most importantly, I think this--the fourth section of chapter one-- doesn't really seem like introductory material. How about a broad overview and discussion of syntax first? Just my opinion.

Thanks for the breakdown. Every little bit helps. So far in chapter one the only discussion of double parens or double brackets is this:
Perhaps it is my intellectual limitations, but I think this is not especially helpful to a Beginner. The O'Reilly book looks like it will probably be more my speed.

I will overcome. I think the book is looking like a good choice. I will say that BASH seems pretty different from Javascript/PHP/Java/C/whatever.

I've got some familiarity. I found the mention of forking off another process somewhat informative and also odd. Why mention process forking before we cover the basics of syntax? Does the primary process go to sleep? Couldn't it just execute the script itself? At what point is the other process forked? Is the script parsed in its entirety first or one line at a time? Does the parent process parse the file or does the child process parse the file?

???

Whoa. Interesting.

This extra space requirement was a source of great confusion. Thank you for laying it bare.

Yeah the book looks readable.

Thank you!