bash: programmatically assemble list - bash

Question

I'm trying to write a shell script which is assembling a list that will later be passed to sort -n. If I do:
find . -type f -printf "%s\n" | sort -n
the output is sorted just as I expect. What I can't figure out is how to assemble the list from inside the script itself. Here is the current script which tries to sum up how much space is used in a directory, sorted by file extension:
#!/bin/sh
echo -n "Enter directory/path to analyze: "
read path
extList=` find $path -type f -print | awk ' BEGIN {FS="."}{ print $NF }' | grep -v '/' | sort | uniq `
for ext in $extList; do
byteList=`find $path -type f -name \*.$ext -printf '%s\n' `
sum=0
for b in $byteList; do
sum=$(( $sum + $b ))
done
sum=$(( $sum/1024 ))
list+=`printf " $sum KB $ext\n"`
done
echo $list | sort -n
I've tried a lot of things for the list+= line, but I don't get a true list. I wind up with everything appearing as a single line, unsorted.

Answer 1

Here's a Minimal, Complete, and Verifiable example of what you're seeing:
echo "$(printf 'foo\n')$(printf 'bar\n')"
Expected:
foo
bar
Actual:
foobar
This is because trailing linefeeds are stripped in the contents of $(..) and `..` command substitution.
Instead, you can use $'\n' or a literal linefeed. Both of these will correctly append a linefeed:
list+="foo"$'\n'
list+="bar
"
Once you fix that, here's your next MCVE:
list="foo
bar"
echo $list
Expected:
foo
bar
Actual:
foo bar
This is due to the lack of quoting in echo $list. It should be echo "$list".
However, none of this is the bash way of doing things. Instead of accumulating into a variable and then using the variable, just pipe the data. This is what you're doing:
list=""
for word in foo bar baz
do
list+="$word"$'\n'
done
echo "$list" | sort -n
This is more canonical:
for word in foo bar baz
do
echo "$word"
done | sort -n

Answer 2

One problem is that `cmd` strips trailing newlines. Another is that echo $list doesn't quote "$list", so newlines are printed as spaces.
There's no need to build a list variable to then sort it later, though. Instead, try sorting all of the loop's output.
for ext in $extList; do
...
printf " %s KB %s\n" "$sum" "$ext"
done | sort -n
I'd suggest not storing the extension list in a string either. You could use a function:
extList() {
find "$path" -maxdepth 1 -type f -printf '%P\n' | awk -F. 'NF>1 {print $NF}' | sort -u
}
extList | while IFS= read -r ext; do
...
done | sort -n
Or store them in an array:
readarray -t extList < <(find "$path" -maxdepth 1 -type f -printf '%P\n' | awk -F. 'NF>1 {print $NF}' | sort -u)
for ext in "${extList[#]}"; do
...
done | sort -n