[Pandamonium]

Hi, I am trying to work on a script in bourne that takes an input file of peoples grades and sorts it based on the total.

I want to take the following

Name	Exam1	Exam2	Exam3
Greg	 63	     72	     70
Scott	 90	     95	     98
Emily	 81	     65	     89

and have the script add a new column with the total scores and sort the people by total:
like so:

Name	Exam1	Exam2	Exam3  total
Scott	  90	  95	   95      280
Emily	  81	  65	   89      235
Greg	  63	  72	   70      205

the input file is grades.txt
I dont know how to get the input file in bourne, or how to grab the values in the individual columns.
Any help would be greatly appreciated. I think I just need a few tips and push in the right direction .

[Pandamonium]

I know I need to create an array using the input file. How do i assign each line to a different variable in an array?

[macosxnerd101]

Did you even do a quick search for a tutorial? I did, and came up with this.

[Pandamonium]

I have actually been using that tutorial sporadically, however it does not explain how to import a line from a file into an array.

[baavgai]

For even the most trivial things, you usually reach out to the rest of the utilities in the environment. Math, for example, isn't really supported in standard Bourne; you need to call something external.

Here's a quick and dirty:

#!/bin/sh

while read LINE; do
	echo $LINE
	ELE_NUM=0
	for WORD in $LINE; do
		echo $ELE_NUM"\t*"$WORD"*"
		ELE_NUM=`expr $ELE_NUM + 1`
	done
done < test.txt

Result:

Name Exam1 Exam2 Exam3
0	*Name*
1	*Exam1*
2	*Exam2*
3	*Exam3*
Greg 63 72 70
0	*Greg*
1	*63*
2	*72*
3	*70*
Scott 90 95 98
0	*Scott*
1	*90*
2	*95*
3	*98*
Emily 81 65 89
0	*Emily*
1	*81*
2	*65*
3	*89*

The shell doesn't really have arrays, but it does tokenize by white space.

I'd probably make a function for the line. Then, you get tokens as params. e.g.

#!/bin/sh

processLine() {
	echo "*"$2"*\t*"$3
}

while read LINE; do
	echo $LINE
	processLine $LINE
done < test.txt

Name Exam1 Exam2 Exam3
*Exam1*	*Exam2
Greg 63 72 70
*63*	*72
Scott 90 95 98
*90*	*95
Emily 81 65 89
*81*	*65

Shell scripting is a game where you figure out which base elements exist in the OS that you can leverage. You can make it a game about using only shell elements, but you'll be fooling yourself; they sneak in all over the place. So, first, you have to define your tool set. Then you can get to work.

[Pandamonium]

Thanks for the help, I was getting myself more and more confused.
few questions though. In the code, how do I tell it to read the names from grades.txt?
also how do I do addition and create a new column?

[baavgai]

Well, name is your first column, so you just print the first.

The rest are values. You can use `expr ` as already shown to add them up.

processLine() {
	echo "Name: "$1
	echo "Exam1: "$2
	echo "Exam2: "$3
	echo "Exam3: "$4
	echo ""
}

[Pandamonium]

cool, I understand how to do the adding and columns now. I am still a little confused as to how the script knows to pull the information from the grades.txt file.
also when trying to run the first part I get this error:
sh-3.2$ chmod +x test.sh
sh-3.2$ ./test.sh
'/test.sh: line 5: syntax error near unexpected token `do
'/test.sh: line 5: ` for WORD in $LINE; do

[baavgai]

Hmm... runs fine here.

Three possibilities I can think of:

• The shebang, #!/bin/sh, isn't pointing to your shell.
  
• What is at #!/bin/sh isn't actually a Bourne shell. ( Bash would be fine, it's a superset. )
  
• Your OS doesn't have a "read" command. Recall I said shell scripts use OS elements, even if you don't notice.

Any normal *nix should come ready to go with a Bourne shell or compatible. If you have something like cygwin, make sure you have installed everything you need.

[Pandamonium]

Ok, it is nolonger giving errors, but when I use the script, nothing shows up in test.txt.

[baavgai]

You're going the wrong direction. The file test.txt is being read. It's piping into the while block. Change it to your grades.txt or whatever.