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    For those (like me) wondering why is the space needed, man bash has this to say about it: > Note that a negative offset must be separated from the colon by at least one space to avoid being confused with the :- expansion.
    – foo
    Commented May 28, 2015 at 3:34
  • 1
    I've been using this and it breaks in MSYS2 bash in windows only. Bizarre.
    – Steven Lu
    Commented Mar 23, 2018 at 18:25
  • 3
    Note: This answer works for all Bash arrays, unlike ${@:$#} which only works on $@. If you were to copy $@ to a new array with arr=("$@"), ${arr[@]:$#} would be undefined. This is because $@ has a 0th element that isn't included in "$@" expansions.
    – Mr. Llama
    Commented Mar 18, 2019 at 17:26
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    @Mr.Llama: Another place to avoid $# is when iterating over arrays since, in Bash, arrays are sparse and while $# will show the number of elements in the array it's not necessarily pointing to the last element (or element+1). In other words, one shouldn't do for ((i = 0; i++; i < $#)); do something "${array[$i]}"; done and instead do for element in "${array[@]}"; do something "$element"; done or iterate over the indices: for index in "${!array[@]}"; do something "$index" "${array[$index]}"; done if you need to do something with the values of the indices.
    – Dennis Williamson
    Commented Mar 18, 2019 at 17:38
  • Works for Bourne shell also, at least for me
    – GregD
    Commented Apr 5, 2021 at 19:50