Why does bash appear to count the words in an array rather than the number of elements?

touch '1 red' '2 orange' '3 yellow'        # Three filenames, each of two words

files=( * )                                # Get the set of files
echo "#files is ${#files}"

for (( i=0; i <= ${#files}; i++ ))
    printf "%d\t%s\n" $i "${files[$i]}"

The output from this seems "wrong". For starters, ${#files} contains 5, showing that there are six elements in ${files[@]}. However, only elements 0, 1, and 2 of ${files[@]} contain any data, and those contain the correct filenames:

#files is 5
0       1 red
1       2 orange
2       3 yellow

I would have expected either ${files[@]} to contain the six words 1, red, 2, orange, 3, and yellow, or ${#files} to be 2. Not this mixed scenario.

Can anyone shed any light on this for me, please?

  • 1
    Try echo "${#files[@]}" instead. – Satō Katsura Oct 12 '16 at 14:27

${#files} is the length of the first element of the array, i.e. the length of 1 red. Which is five.

From the manual:

${#name[subscript]} expands to the length of ${name[subscript]}. If subscript is ‘@’ or ‘*’, the expansion is the number of elements in the array. [...]
Referencing an array variable without a subscript is equivalent to referencing with a subscript of 0.

So, ${#files} = ${#files[0]}. But ${#files[@]} or ${#files[*]} give the number of elements in the array.

(It has nothing to do with the number of words, though if you expand ${files[*]} without quotes, you get the usual word splitting over all the values.)

  • Bit of an annoying feature, I'd say, but I guess it's in line with conflating ${array[0]} with $array. – ilkkachu Oct 12 '16 at 14:51
  • If it's counting words in the 0th element, why does ${#files} in my example show 5 not 2 (or 1)? – roaima Oct 12 '16 at 14:54
  • 1
    It's not counting words, just the characters. – ilkkachu Oct 12 '16 at 15:08

Please Change ${#files}" to ${#files[@]}"

You are getting 5 from ${#files}" because that is the first file.
Equivalent to ${files[0]}, which is named '1 red'.
That string contains 5 characters.

The loop fails for the same problem, it iterates from 1 to 5.
However, elements 3, 4 and 5 are simply null (unset).

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