Odd numbers arithmetic syntax error in alphine image - bash

Question

I want to print odd numbers in alpine:3.13 image. I'm getting the error, line 4: arithmetic syntax error. However, this works fine in linux. How can I fix this? Thanks!

for i in {1..10}
do
    if [ $(( $i % 2 )) != 0 ]
    then
      echo "$i"
    fi
done

When I change the first line with this for i in 1 2 3 4. It works fine but I need to give a range. Any help would be appreciated

You should use `-ne` for arithmetic comparisons, although I can't think of a reason why `!=` wouldn't work in this case. — Barmar, Apr 05 '21 at 23:48
I am running it on alpine:3.13 image, that causes the issue. It works good in mac — cosmos-1905-14, Apr 05 '21 at 23:48
@Barmar I tried that one, it didnt work. I guess the issue is in the first line, because when I make it for i in 1 2 3 4 it works — cosmos-1905-14, Apr 05 '21 at 23:50

score 0 · Accepted Answer · answered Apr 05 '21 at 23:52

0

Brace notation for ranges is a bash extension, which is apparently not available on Alpine.

Use $(seq 1 10) instead:

for i in $(seq 1 10)

answered Apr 05 '21 at 23:52

Barmar

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500
612

score 0 · Answer 2 · answered Apr 06 '21 at 00:22

0

You can try using a more portable syntax.

i=0
while [ "$i" -lt 10 ]; do
  if [ $(( $i % 2 )) != 0 ]
    then
      echo "$i"
    fi
  i=$((i + 1))
done

answered Apr 06 '21 at 00:22

Jetchisel

7,493
2
19
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Odd numbers arithmetic syntax error in alphine image - bash

2 Answers2