Shell Programming and Scripting

Hello! i try to understand the art of bash scripting but unfortunately, more i try and less i understand it.
Can someone tell me how i can learn its logic? i will give you an example why its making me crazy. Look at this basic script:
my for loops are working like this, but it took me more than one hour because "for" is not in yellow. Is it a bug?

I also need help to compare table items in the second for loop.
Please don't give me another way to do it, i just try to understand syntax logic.
I swear i've tried to do it alone but no way.
Sorry, i m not good in english

ps: in fact, the first for loop is working, the second give an an error. Of course i 've changed the second one.

Hi could you post the text version instead of a picture?

There are several problems I noticed:
--
I don't understand why in this case the for statement gets highlighted in a different color within a function though.

Welcome to the forum.

Please - don't post pictures of your code, although your nice colour scheme might be lost if you copy & paste text into your post. And, post your OS and shell versions. And, very important, tell people in here WHAT doesn't behave, and HOW, so errors can be tracked.

"for is not in yellow" certainly is not a bug. Some editors help your get the syntax right by trying to interpret your code and then colourise the parts that it recognizes. So - if there was a bug, it would be somewhere upfront, confusing the editor in its syntax check. Quite often it's missing (closing) quotes or parentheses...
The only error that jumps to my eyes on first sight is the missing / wrong break condition in the innermost for loop.

Thank you for help me. I'm sorry those mistakes are very stupids. Also i forgot a "t" at $tableau in the last for. Now it's working but "for" is still in grey, so i suppose there's a litlle error somewhere. I give you the working code if you want to look for it.

If you can give me some good tutorial to understand some logic basis... for example when use (( or { , also the diference between " and quotes... you understand what i mean?

Code:

 #!/bin/bash

if [ $# -gt 1 ]
then 
	declare -a tableau
	idx=0
	for i in "$@"
	do
			tableau[$idx]=$i
			((idx++))

	done
fi

tri(){
	for ((i=0;i < $idx;i++))
	do	
		recom=0
		for ((a=0;a < $idx ;a++)) 
		do 
			if [ ${tableau[$i]} -lt ${tableau[$a]} ]
			then
				tempor=${tableau[$i]}
				tableau[$i]=${tableau[$a]}
				tableau[$a]=$tempor
				recom=1
			fi
		done

		if [ $recom -eq 1 ]
		then 
			((i--))
		fi
	done
}

tri
echo ${tableau[@]}

Have a look at : LMGTFY

BTW, you can simplify the creation of your tableau array to

Code:

tableau=("${@}")

Note also that your variable idx, refered to in function tri, is empty if your script is called without parameters.

thank you rovf. I know google lol but all tutorials i found tell how to do but don't explain the logic. I would like to be able to understand. Right now i often need to use google. What i want is to be able to write a script without it. I don't have syntax problem with C or java but with bash i'm very disapointed. Maybe I'm wrong but i think there's no "universal" syntax. I mean, sometimes i look at "resolved problems", i copy/paste the code but it's not working for me. RudiC asked me which version i use, so I suppose there are differences...
I'm very interested in learning sytem and networking administration, it's very interesting but i must be able to write scripts to automate tasks. That's my only problem right know.

If you know programming languages like C or java, you are able to cope with (bourne type) shells. The logics is not too different from the formers', the syntax might be. It's just a matter of exercise. If copy / pasted code doesn't work for you, you indeed should compare the versions. All shells, be it bash or ksh or what have you, evolve over time, and functionality found in recent ones may not be available in older versions. Same is true between shells - although bash and ksh both are descendants of the original sh, and are generally compatible with each other, there are parts in each that don't work in the other.
Run your code, and post it as well as shell version, results and errors in here to be analysed and commented on.