Loop over set of strings containing spaces

Question

I have multiple strings like "a b", "c d", "foo bar" and so on. I want to loop over this set of string and perform an action on each of these. In this action I call multiple other scripts so I do not want to change IFS for this loop since it could break my invocation of other scripts. This is why I try to escape the spaces contained in these strings but without success.

So for instance I expect to get

a b c d 

And I tried the following:

#!/bin/sh  x="a b" y="c d"  echo "Attempt 1" all="$x $y"  for i in $all ; do   echo $i done  echo "Attempt 2" all="a\ b c\ d" for i in $all ; do   echo $i done  echo "Attempt 3" all=($x $y) for i in ${all[@]} ; do   echo $i done  echo "Attempt 4" all='"'$x'" "'$y'"' for i in $all ; do   echo $i done  echo "Attempt 5" for i in "$x" "$y" ; do   echo $i done  echo "Attempt 6" all2=("a b" "c d"); for i in ${all2[@]}; do   echo $i done  echo "Attempt 7" all3="a b c d" echo $all3| while read i; do   echo $i  done  

Only attempt 5 succeeds, but I would like to do this without having to declare one variable per string, (it would be painful to maintain). I just introduced x and y for testing but the idea is to declare in one variable the set "a b" and "c d".

Answer 1

You need to wrap the variables within double quotes, both in all=("$x" "$y") and "${all[@]}":

x="a b" y="c d"  echo "Attempt XX" all=("$x" "$y") for i in "${all[@]}" ; do   echo "$i" done 

Which yields:

Attempt XX a b c d 

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You can also define the strings with:

all=("a b" "c d") for i in "${all[@]}" ; do   echo "$i" done