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up vote 4 down vote favorite
1

I want to accomplish the equivalent of:

list=()
while read i; do
  list+=("$i")
done <<<"$input"

with

IFS=$'\n' read -r -a list <<<"$input"

What am I doing wrong?

input=`/bin/ls /`

IFS=$'\n' read -r -a list <<<"$input"

for i in "${list[@]}"; do
  echo "$i"
done

This should print a listing of /, but I'm only getting the first item.

share|improve this question
4  
If you are really trying to parse the output of ls, don't. Use list=(/*). – chepner Nov 23 '15 at 14:50
up vote 6 down vote

You must use mapfile (or its synonym readarray, which was introduced in bash 4.0):

mapfile -t list <<<"$input"

One read invocation only work with one line, not the entire standard input.

read -a list populate the content of first line of standard in to the array list. In your case, you got bin as the only element in array `list.

share|improve this answer
    
For anyone working with older versions of Bash, this feature was introduced with Version 4. – Anthony Geoghegan Nov 23 '15 at 12:43
1  
@AnthonyGeoghegan: Forgot to mention it, added! – cuonglm Nov 23 '15 at 12:49
2  
@cuonglm The IFS is useless, because mapfile doesn't do any word-splitting on its input. – chepner Nov 23 '15 at 14:47
    
@StéphaneChazelas: My bad, removed it. – cuonglm Nov 23 '15 at 15:34
    
@chepner: Thanks, I removed it. – cuonglm Nov 23 '15 at 15:37
up vote 3 down vote

for bash versions that do not support mapfile

IFS=$'\n' read -ra list -d '' <<< "$input"

should do the trick

share|improve this answer
2  
One minor drawback; this command will always have a non-zero exit status. – chepner Nov 23 '15 at 14:46
2  
Also note that it removes empty elements. – Stéphane Chazelas Nov 23 '15 at 16:47
up vote 3 down vote

Solution for Bash version 3 (and 4)

I happened to be logged in to a CentOS 5 box running Bash 3 and I had been working on a solution. I’ve already upvoted cuonglm’s answer but I thought I may as well post the solution I came up with that should work with Bash 3 (and 4). I’ve tested it with a file which had a space in its name and another which begins with -.

Instead of

IFS=$'\n' read -r -a list <<<"$input"

simply use command substitution to create and populate the array:

IFS=$'\n' # split on newline only
set -f    # disable globbing
list=($(printf "%s" "$input"))

Note: This won’t work with filenames which have newlines in their name.

share|improve this answer
    
@StéphaneChazelas Thanks for the edit (adding set -f). I was assuming that since the OP was setting the contents of input to the output of /bin/ls that it wouldn't contain glob patterns -- but that isn't necessarily the case. – Anthony Geoghegan Nov 23 '15 at 16:58

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