Switch statement with case

With the case statement you can match values against one variable.

The argument passed to case is expanded and try to match against each patterns.

If a match is found, the commands upto ;; are executed.

case "$BASH_VERSION" in
 [34]*)
    echo {1..4}
    ;;  
  *)
    seq -s" " 1 4
esac

Pattern are not regular expressions but shell pattern matching (aka globs).