Printing output of C program in shell script

Question

I have a program where I have to take a c program that converts fro kelvin to far and vice versa. I need help with the output, it should read from a data file that I put in $file and the $choice from user and run it the the c program file .farh_kel

while read val
do
      ans=`.fahr_kel $choice $val`
      echo $line
      echo $ans
done < file

MY OUTPUT SHOULD LOOK LIKE THIS

---------------------- -----------------------
           0                   256
---------------------- -----------------------
           32                  273
---------------------- -----------------------
           100                 310
---------------------- -----------------------
           212                 373
---------------------- -----------------------
           108                 315
---------------------- -----------------------
           1243                945
---------------------- -----------------------
           3000                1921
---------------------- -----------------------
            853                02
---------------------- -----------------------
            22                 268
---------------------- -----------------------
           2388                1581
---------------------- -----------------------
            235                 385
---------------------- -----------------------

Instead it looks like this :

---------------------- -----------------------
 0 256
---------------------- -----------------------
 32 273
---------------------- -----------------------
 100 310
---------------------- -----------------------
 212 373
---------------------- -----------------------
 108 315
---------------------- -----------------------
 1243 945
---------------------- -----------------------
 3000 1921
---------------------- -----------------------
 85 302
---------------------- -----------------------
 22 268
---------------------- -----------------------
 2388 1581
---------------------- -----------------------
 235 385
---------------------- -----------------------

This doesn't really have anything to do with C, and certainly not with cross compiling. Nor is it even specific to Unix or Linux. Tags edited. — John Bollinger
– John Bollinger, Commented Apr 27, 2017 at 18:40
Putting a . at the beginning of a program name is very strange style. Usually an initial . is used for files and directories that should be hidden by default, like startup and configuration files. Did you mean to write ./fahr_kel? — Barmar
– Barmar, Commented Apr 27, 2017 at 18:41
john well eveyone else got it so whats your point? it actually has everything to do with c do to the fact that my coding that run the math for this program is a c code complied in bash — April Renee
– April Renee, Commented Apr 27, 2017 at 19:49

Barmar · Accepted Answer · 2017-04-27 18:38:13Z

2

Quote your variable to prevent the shell from combining all the spaces:

echo "$ans"

Or don't assign it to a variable in the first place, just let the program print its output normally.

while read val
do
    echo "$line"
    .fahr_kel "$choice" "$val"
done < file

In general, you should always quote variables unless you specifically want to allow word splitting and wildcard expansion of its contents.

answered Apr 27, 2017 at 18:38

Barmar

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2 Comments

April Renee Over a year ago

having trouble with output project3.sh > project3.output isnt working when placed at the end of my script

Barmar Over a year ago

@AprilRenee I'm not sure what that means. It sounds like a new question.

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