Calling an executable within a nested for loop in linux

Question

I am trying to call an executable with two arguments within a nested for loop (I'm also writing in bash scripting). I thought I was doing it correctly, but all my values show up in the text file as 0. i.e. tilt 0 angle 0 even though the values are obviously not. My code is as such:

for (( i=0; i <=3; i++)); do
    for (( j=0; j <= 3; j++ )); do
        ./solar_sim 'i' 'j' >> solarResults.txt
        echo -n "$i"
    done
    echo " "
done

`

The solar_sim was provided to us and output a line like this, which I write to a file:

10000 hours, angle: 0.00 degrees, temperature: 0.00 degrees C, total power: 119871.00 Watts Am I doing something wrong in the calling of solar_sim? I also tried using $i and $j

Gilles Quénot · Accepted Answer · 2013-02-18 01:09:54Z

2

Your mistake is this line :

./solar_sim 'i' 'j' >> solarResults.txt

should be rewritten like this :

./solar_sim "$i" "$j" >> solarResults.txt

Also, echo is sufficient alone, no need echo " " to print a newline

answered Feb 18, 2013 at 1:09

Gilles Quénot

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4 Comments

scoots Over a year ago

Oops! Forgot the double quotes. Thanks so much!

Gilles Quénot Over a year ago

Not only the double quotes but the sigils

scoots Over a year ago

I'm pretty new to bash scripting, so I was experimenting. Got the sigils in. Thanks. Will upvote when able

scoots Over a year ago

Yes, I know. I had to wait the required amount of time. No need to be rushed!

EJK · Accepted Answer · 2013-02-18 01:11:25Z

-1

It looks like you forgot the "$" to de-reference the i and j variables

./solar_sim "$i" "$j" >> solarResults.txt

answered Feb 18, 2013 at 1:11

EJK

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2 Comments

Gilles Quénot Over a year ago

Where's there's references ? This is just some basic variables... And in single quotes, variables are not interpolated !

EJK Over a year ago

Excuse me if my terminology is not perfect. It sure looked to me like the script was intending to reference the variables value.

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