I will have @mrnoname1000 look at this since he has helped with this script recently. The original introduction of basename -- appears to have been a long time ago in b1fec0d and I'm pretty sure I just got it off some SO post or blog entry somewhere.

I was just testing something and I got a weird error at startup. I didn't find any similar report, but probably there aren't many Solaris users of JRuby.
I'm definitely not an expert on Bash & Solaris, so maybe there's a better way.

https://unix.stackexchange.com/questions/253524/dirname-and-basename-vs-parameter-expansion

Looks like POSIX doesn't allow options to basename, so this is another GNU-ism we need to work around. Fortunately, basename operates purely on text, so it's pretty easy to implement in pure shell:

basename() {
    local base="$1"
    if [ -n "$base" ]; then
        # remove trailing slashes
        base=${base%"${base##*[!/]}"}
        # remove leading directories
        base=${base##*/}
        # if $1 is all slashes, base=/
        base=${base:-/}
    fi
    printf "%s\n" "$base"
}

The printf can be replaced with an alternate return method to avoid a subshell, such as RET=$base.

Also basename has a little-used feature to remove a suffix, this function doesn't implement that.

@mrnoname1000 Perhaps I should merge this as-is and you can push another PR with the pure-POSIX basename change?

Actually I overlooked that stackexchange link, the implementation there looks better than mine and seems more efficient. I'll create a PR with that instead.