How to access last item in bash array on Mac OS?

Question

I had to create a bash array on Mac OS as follows. The $1 represents # of git commits you want to store in the array.

IFS=$'\n' read -rd '' -a array<<< "$(git log -n $1 | grep commit |  awk '{print $2}')"

I can't access last array item as ${array[-1]}. I get the error "array: bad array subscript".

However, when I create the array on linux OS, I can access the last array item in the same way successfully.

readarray -t array <<< "$(git log -n $1 | grep commit |  awk '{print $2}')"

echo ${array[-1]} is successful on Linux machine but not on Mac OS machine.

Apple ships bash 3.2; this is ancient -- current releases are in the 5.x series. You have the option to install a newer one with Nix, MacPorts, Homebrew, etc. — Charles Duffy
– Charles Duffy, Commented Apr 3, 2020 at 2:18
Closely related (but assumes the answer to this question as a premise): get last element in bash array — Charles Duffy
– Charles Duffy, Commented Apr 3, 2020 at 2:21

Charles Duffy · Accepted Answer · 2020-04-03 02:20:16Z

2

In a bash too old to support negative subscripts, you end up needing to do something like:

echo "${array[$((${#array[@]} - 1))]}"

1 Answer 1