Convert a string into an array with bash, honoring quotes for grouping [duplicate]

Answer 1

If you already know the index of the words you are looking for, converting a string to an array is as simple as using parentheses:

tmp=($(echo $Str))

Then you can just echo ${tmp[4]} ${tmp[5]} to print "a substring" without the commas.

However, if you already know what the substring is, why not grep it from the original?

echo $Str | grep -o "a substring"

will return the substring in the same manner, but you won't need to worry about the length of the substring or the index of the words inside the array.

Edit: By the way, if you just wanted to remove the first and last character of any string you could do (bash 4.2 and above):

echo ${Str:1:-1}

Answer 2

This problem requires the use of xargs (it retains quoted strings together):

$ Str='This string has "a substring"'
$ IFS=$'\n' arr=( $(xargs -n1 <<<"$Str") )
$ printf '<%s>\n' "${arr[@]}"
<This>
<string>
<has>
<a substring>

So, the element you need:

$ echo "${Tmp[3]}"
a substring

---

Please note that leading or trailing white space will be removed for "unquoted" items:

$ Str='  This    string    has "   a substring  "'
$ IFS=$'\n' arr=( $(xargs -n1 <<<"$Str") )
$ printf '<%s>\n' "${arr[@]}"
<This>
<string>
<has>
<   a substring  >

Answer 3

Give a try to this:

 Str='this string has "a substring"'
 eval Tmp=( "${Str}" )

 printf "%s\n" "${Str}"
 this string has "a substring"

 printf "%s\n" "${Tmp[3]}"
 a substring

 set | grep "^Tmp"
 Tmp=([0]="this" [1]="string" [2]="has" [3]="a substring")

I have to warn you regarding eval, see the comment from @charlesduffy: use it only if Str is generated earlier with your own lines of code.