The operator in table 6 allow vector and string subscriptions. A ${@: }-operator performs string subscription, a ${@ }-operator performs vector subscription. If only one index is specified, than only one specific element is returned. If two indices are given, the substring/sub-vector from the first to the last index is returned. If the second index is '-1' it is considered to be equal to the size of the vector/string.
| ${@: string index0} | specific letter in string |
| ${@: string index0 index1} | substring in string |
| ${@ variable index0} | specific element in vector variable |
| ${@ variable index0 index1} | sub-vector in vector variable |