Array of arrays in bash

Question

I\'m attempting to read an input file line by line which contains fields delimited by periods. I want to put them into an array of arrays so I can loop through them later on

Answer 1

You could make use of (de)referencing arrays like in this script:

#!/bin/bash

OFS=$IFS     # store field separator
IFS="${2: }" # define field separator
file=$1      # input file name

unset a      # reference to line array
unset i j    # index
unset m n    # dimension

### input

i=0
while read line
do
  a=A$i
  unset $a
  declare -a $a='($line)'
  i=$((i+1))
done < $file
# store number of lines
m=$i

### output

for ((i=0; i < $m; i++))
do
  a=A$i
  # get line size
  # double escape '\\' for sub shell '``' and 'echo'
  n=`eval echo \\${#$a[@]}`
  for (( j = 0; j < $n; j++))
  do
    # get field value
    f=`eval echo \\${$a[$j]}`
    # do something
    echo "line $((i+1)) field $((j+1)) = '$f'"
  done
done

IFS=$OFS

Credit to https://unix.stackexchange.com/questions/199348/dynamically-create-array-in-bash-with-variables-as-array-name