Shell - putting strings in a vector has a strange behavior with spaces

Question

I have to ask you this because its driving me crazy since too many days.

I will explain my problem with an example:

s1="aa a"
s2="bbb"
s3="ccc"
s4="ddd"

v=($s1 $s2 $s3 $s4)
echo ${v[0]}
echo ${v[1]}
echo ${v[2]}
echo ${v[3]}
echo ${v[4]}

The output is:

aa
a
bbb
ccc
ddd

My problem is that v[0] contains "aa" and v[1] contains "a". I don't get why v[0] is not "aa a".

My output should be:

aa a
bbb
ccc 
ddd

...and v[4] should be empty

Why does the space create this problem?

For reference, this answer explains when to use quotes around a shell variable: https://stackoverflow.com/a/10067297/5411198 — builder-7000, May 04 '18 at 17:15
Note once you declare the array `v=("$s1" "$s2" "$s3" "$s4")` you can print its values as: `for ((i=0; i<${#v[@]}; i++)); do echo ${v[i]}; done` (bash). — builder-7000, May 04 '18 at 17:25

Ronan Boiteau · Accepted Answer · 2018-05-04T17:04:58.227

0

You need to add double quotes around your variables, like this:

v=("$s1" "$s2" "$s3" "$s4")

...so that you get:

v=("aa a" "bbb" "ccc" "ddd")

It is generally always a good idea to put your variables inside double quotes.

Without quotes you get the following:

v=(aa a bbb ccc ddd)

...so aa & a are interpreted as 2 separate strings.

edited May 04 '18 at 17:04

answered May 04 '18 at 16:58

Ronan Boiteau

1 Answers1