for loop not working for multiple lines

Question

I have a array like this "Apple Banana Clementine Date"

I have to print like this:

1. Apple
2. Banana
3. Clementine
4. Date

Script file:

for i in "${fruits[@]}"; do
    echo "$lineno. $i "
    lineno+=1
done

output of myscript:

1.             Apple
               Banana
               Clem....

I don't understand why it is not printing lineno and also why it is printing long gap b/w 1. and Apple. Thanks.

Answer 1

The problem is your array. It seems that you have created an array with only one element. Try this example:

array=("$(printf 'Apple\nBanana\nClementine\nDate')")

for ((i = 0; i < ${#array[@]}; i++)); do
  printf '%d. %s\n' $((i+1)) "${array[$i]}"
done

j=0
for e in "${array[@]}"; do
  j=$((j+1))
  printf '%d. %s\n' "$j" "$e"
done

k=0
for e in ${array[@]}; do
  k=$((k+1))
  printf '%d. %s\n' "$k" "$e"
done

Then run:

$ ./test.sh 
1. Apple
Banana
Clementine
Date
1. Apple
Banana
Clementine
Date
1. Apple
2. Banana
3. Clementine
4. Date

You can see, you actually create an array contains one element. The 3rd loop print four elements because the shell had performed field splitting on string Apple\nBanana\nClementine\nDate, which gave you four separated words back.

If you change the array to:

set -f
array=( $(printf 'Apple\nBanana\nClementine\nDate') )
set +f

(set -f disables wildcard expansion, in case the characters *?\[ appear in the output of the command) you will get the desired result, which is that the output of the command is split at whitespace:

$ ./test.sh 
1. Apple
2. Banana
3. Clementine
4. Date
1. Apple
2. Banana
3. Clementine
4. Date
1. Apple
2. Banana
3. Clementine
4. Date

A note that you must use double quotes "${array[@]}" when you want to iterate through all array elements, or use the c-style for loop like my first example.

Answer 2

This is what you need:

[sreeraj@server ~]$ fruits=(Apple Banana Clementine Date)
[sreeraj@server ~]$ (IFS=$'\n'; echo "${fruits[*]}") | nl
     1  Apple
     2  Banana
     3  Clementine
     4  Date
[sreeraj@server ~]$