In some case, quotes can solve a param which contains space.
$ command "param 1" "param 2" ...
And it can also work for for loop.
$ for v in a "b c" "d e"
do
echo "|$v|"
done
|a|
|b c|
|d e|
But when I use a variable after in, it not working:
$ var='a "b c" "d e"'
$ echo $var
a "b c" "d e"
$ for v in $var
do
echo "|$v|"
done
|a|
|"b|
|c"|
|"d|
|e"|
It not working. How do I resolve this problem ?
That is why arrays were invented:
$ var=(a "b c" "d e")
$ for v in "${var[@]}"; do echo "|$v|"; done
|a|
|b c|
|d e|
Consider:
var='a "b c" "d e"'
The problem with the above is that, once you quote a quote, it loses its magic. The double-quotes inside the single-quoted string above are characters, just like any other characters: they no longer bind anything together. That is why the output looks like this:
|a|
|"b|
|c"|
|"d|
|e"|
Arrays can be entered in newline-separated form using readarray:
$ readarray -tn3 var
a
b c
d e
$ for v in "${var[@]}"; do echo "|$v|"; done
|a|
|b c|
|d e|
-n3 limits the input to three lines. -t tells readarray to discard the newline character.
read -p to get string args. Like this: read -p "Please input some args: " str; var=($str) ; But it not working.
str, unfortunately, their magic has been lost. bash does provide readarray for getting arrays from the terminal. See the example in the updated answer.As mentioned in comments and another answer, use an array if you can. That really is the best option.
If you are forced to work with strings (for some odd reason not described in your question) change your internal field separator, and then use your custom defined one to separate fields.
#Copy the current IFS
SaveIFS=$IFS
IFS=';'
var='a;b c;d e;'
for v in $var; do
echo $v
done
#Revert when done
IFS=$SaveIFS
IFS is not a good solution. It will affect other command.