bash check is string contains substring not working

Question

When I execute below script it works fine:

if [[ "[1,2,3]" =~ .*1.* ]]; then
techStatus=1
else 
techStatus=0;
fi
echo $techStatus

Output is 1

But when we changes it to variable it does not work.

var1=[1,2,3]
var2=1
if [[ "$var1" =~ .*"$var2".* ]]; then
techStatus=1
else 
techStatus=0;
fi
echo $techStatus

Output is 0.

Please help me figure out what is wrong here.

Try var1=“[1,2,3]” putting quotes on your variables also you are supposed to write vars ${var1} opposed to $var1 but unrelated minor comment. — Mike Q, Sep 23 '18 at 10:52
@MikeQ While both good habits, they make no difference in this case. — Biffen, Sep 23 '18 at 10:59
See your code with no changes whatsoever working in the online interpreter at https://ideone.com/rtECyG — Charles Duffy, Sep 23 '18 at 14:51
Also, note that this doesn't generalize to JSON documents as a whole. You don't want to match `10` because it contains `1`, or a list that contains `"This is a string, not a number at all, but it contains ,1, in its text"` but no entry with just a `'`. — Charles Duffy, Sep 23 '18 at 14:53

score 0 · Accepted Answer · answered Sep 23 '18 at 14:33

0

A better & readable approach would be to convert var1 to array and loop through var1.

var1=(1 2 3)
var2=1
for elem in "${var1[@]}"; do
    if [[ "$elem" -eq "$var2" ]]; then
        techStatus=1
        break
    else
        techStatus=0
    fi
done
echo "$techStatus"

answered Sep 23 '18 at 14:33

apatniv

1,393
7
11

1

Key by array indices and you don't even have to loop. `var1=( [1]=1 [2]=1 [3]=1 ); if [[ ${var1[$var2]} ]]; then techStatus=1; else techStatus=0; fi` -- if the keys can be non-numeric that means making it an associative array, but that's not much of a change. – Charles Duffy Sep 23 '18 at 14:52
1

...that said, posing this as an answer implies that you think the question could be closed as a duplicate of [check if a bash array contains a value](https://stackoverflow.com/questions/3685970/check-if-a-bash-array-contains-a-value), insofar as the essential elements are all covered there. – Charles Duffy Sep 23 '18 at 18:30

bash check is string contains substring not working

1 Answers1