bash each two elements into array

Question

I have text and each line breaker, I store it the value in array and I display it :

var=("AAA
      aaa
      BBB
      bbb
      CCC
      ccc")

SAVEIFS=$IFS
 IFS=$'\n'
var=($var)
IFS=$SAVEIFS

for (( i=0; i<${#var[@]}; i++ )) do
  echo "${var[$i]}"
done

output :

   AAA
   aaa
   BBB
   bbb
   CCC
   ccc

but I want two first element in the same index array with the line breaker inside each element, like that

 var[0]=("AAA
         aaa")
  var[1]=("BBB
         bbb")
   var[2]=("CCC
         ccc")

Why is var an array when it has only a single element? Just use var=("AAA" "aaa" "BBB" "bbb" "CCC" "ccc"). If that string comes from an external source and you have to split it by line, use readarray -t var <<< "$str" instead of var=("$str"). — chepner
– chepner, Commented Feb 18, 2019 at 16:05
Then it's just a matter of array slicing. var2+=("${var[*]:i:2}") for i=0,2,4,.... — chepner
– chepner, Commented Feb 18, 2019 at 16:06

glenn jackman · Accepted Answer · 2019-02-18 16:38:08Z

2

If you declare the array using bash ANSI-C Quoting

ary=($'AAA\naaa' $'BBB\nbbb' $'CCC\nccc')

Then you get what you are after.

Inspecting the contents of the array

$ declare -p ary
declare -a ary='([0]="AAA
aaa" [1]="BBB
bbb" [2]="CCC
ccc")'

Or inspect it with printf:

$ printf '>%s<\n' "${ary[@]}"
>AAA
aaa<
>BBB
bbb<
>CCC
ccc<

You can't write

 var[0]=("AAA
         aaa")

because, with the parentheses, you are attempting to store an array in an array element, and bash does not allow arrays-of-arrays.

You could write

var=(
"AAA
aaa"
"BBB
bbb"
"CCC
ccc"
)

If you have an array of words like var=(AAA aaa BBB bbb CCC ccc) then you could group elements together like this:

ary=()
for (( i=0; i < ${#var[@]}; i+=2 )); do
    ary+=( "${var[i]}"$'\n'"${var[i+1]}" )
done

answered Feb 18, 2019 at 16:38

glenn jackman

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