Using bash to get Two variables in for-loop form two different lists

Question

I'm working with bash and I have two lists:

Using the bash code below:

for f1 in AZU SJI IOP
do
    for f2 in A1 B1 C1
    do
        echo $f1 + $f2
    done
done

I get this result:

$ bash dir.sh
AZU + A1
AZU + B1
AZU + C1
SJI + A1
SJI + B1
SJI + C1
IOP + A1
IOP + B1
IOP + C1

I would like to get the result in this way

AZU A1

SJI B1

IOP C1

From How do I ask a good question?: "DO NOT post images of code, data, error messages, etc. - copy or type the text into the question" — Ted Lyngmo
– Ted Lyngmo, Commented Jul 13, 2021 at 8:21
you want three resulting lines, so don't use two nested for loops or you'll have 3*3=9. Use one for loop iterating over 0 to 2, then use that number to index both lists. Moreover you've seen that + isn't a concatenation operator and will appear in the output, so just avoid it. — Aaron
– Aaron, Commented Jul 13, 2021 at 11:37
Does this answer your question? zip columns from separate files together in bash — alecxs
– alecxs, Commented Jul 13, 2021 at 11:38

chepner · Accepted Answer · 2021-07-13 18:46:26Z

1

Define two arrays such that they have the same indices, then iterate over the indices of one array:

list1=(AZU SJI IOP)
list2=(A1 B1 C1)

for i in "${!list1[@]}"; do
  echo "${list1[i]} ${list2[i]}"
done

answered Jul 13, 2021 at 18:46

chepner

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Comments

Armali · Accepted Answer · 2021-07-13 18:43:40Z

1

You could of course use paste, but since your lists are not in files, you might be interested in a solution without external commands:

set -- A1 B1 C1
for f1 in AZU SJI IOP
do  echo $f1 $1
    shift
done

answered Jul 13, 2021 at 18:43

Armali

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