在Unix Shell脚本中嵌套for循环

Question

I have two variables named A and B for files subject and Scores like below

A=contents of file 'subject' which contains "English Hindi Telugu"

B=contents of file 'Scores' which contains "60 60 10"

i want to tag the subject with marks in respective way ie

english ==> 60 hindi ==> 60 telugu ===>10

i implemented as below but its showing weird results:

English ==> 60 English ==> 60 English ==> 10 Hindi ==> 60 
Hindi ==> 60 Hindi ==> 10 Telugu ==> 60 Telugu ==> 60 Telugu ==> 10

I want the results to be like below English ==> 60 Hindi ==> 60 Telugu ==> 10

#!/bin/ksh
A=`cat subject`
B=`cat Scores`
for sub in $A
do
   for score in $B
   do
    echo " $sub ==> $score "
   done
done

Answer 1

This would be somewhat easier if the words in the files appeared on separate lines, such as

$ cat subject
English
Hindi
Telugu
$ cat Scores
60
60
10

Then use some nifty Unix philosophy:

$ paste subject Scores | sed 's/\t/ ==> /'
English ==> 60
Hindi ==> 60
Telugu ==> 10

The paste utility takes care of opening multiple files and reading them line by line, in sync.

To convert your original files, use something like this:

$ printf '%s\n' $(cat subject)
English
Hindi
Telugu

Answer 2

Am not sure what is your actual use-case doing this, but you can define two file-descriptors and read it together and print them together using printf

#!/bin/bash

while IFS= read -r subjectVal <&4 && IFS= read -r scoreVal <&3; do
    printf "%s%s\t" "$subjectVal"" ==> ""$scoreVal"   # To have them all in a single-line
  # printf "%s%s\n" "$subjectVal"" ==> ""$scoreVal"   # To print them in new-lines
done 4<subject 3<scores

printf "\n"

Running the script as ./script.sh would produce an output something like:-

English ==> 60  Hindi ==> 60    Telugu ==> 10