SC2051

Bash doesn't support variables in brace expansions.

Problematic code:

for i in {1..$n}
do
  echo "$i"
done

Correct code:

for ((i=0; i<n; i++))
do
  echo "$i"
done

Rationale:

In Bash, brace expansion happens before variable expansion. This means that brace expansion will never account for variables.

Use an arithmetic for loop instead.

Contraindications

None (if you're writing for e.g. zsh, make sure the shebang indicates this so shellcheck won't warn)