Using an array of strings with spaces in bash - error messages "curl: could not resolve host"

Question

I am attempting to write a script in bash that monitors certain aspects of a server, and sends a message to slack if it notices that something is wrong. However, I am running into a strange set of error messages that leads me to believe the syntax of my script is a little off. Here is the code in question:

message=("Please go to this website: www.google.com" "Please go to this website: www.github.com" "Please go to this website: www.wikipedia.com") for j in seq `0 2`; do curl -X POST -H 'Content-type: application/json' --data '{"text":"<!channel> '${message[$j]}' "}' https://hooks.slack.com/services/AN_ID/ANOTHER_ID/SOME_ID# Slack with channel mention done 

When I run this code, it should send a message to the specified slack group, stating each of the specified lines of text, for example "@channel Please go to this website: www.google.com"

When I run this, I receive the following error messages:

curl: (6) Could not resolve host: go curl: (6) Could not resolve host: to curl: (6) Could not resolve host: this curl: (6) Could not resolve host: website: curl: (3) [globbing] unmatched close brace/bracket in column 34 invalid_payloadcurl: (6) Could not resolve host: go curl: (6) Could not resolve host: to curl: (6) Could not resolve host: this curl: (6) Could not resolve host: website: curl: (3) [globbing] unmatched close brace/bracket in column 33 

Does anybody have any insights on how to resolve these error messages? I am thinking it has something to do with the way I have written the array of strings, but I can't identify the issue.

Answer 1

The problem is not due to the declaration of the array, but the way you access elements. See This post

So, to quote the original answer from SO:

for ((i = 0; i < ${#message[@]}; i++)) do echo "${message[$i]}" done 

It works fine on my side

(Panki's suggestion is right, remove backtick around seq arguments. You can use $(seq 0 2) instead. However, this does not fix the issue)

Answer 2

For readability, I would do this:

messages=( "first" "second" ... ) curl_opts=( -X POST -H 'Content-type: application/json' ) data_tmpl='{"text":"<!channel> %s "}' url=https://hooks.slack.com/services/... for msg in "${messages[@]}"; do curl "${curl_opts[@]}" --data "$(printf "$data_tmpl" "$msg")" "$url" done