4 ms·Or, more simply, $((i + 1)). And it's not only bash; it's feature of POSIX shell.by jwilk 4y agoOr, more simply, $((i + 1)). And it's not only bash; it's feature of POSIX shell.shrewm 4y agoOr as they did in ancient times $[i+1]jwilk 4y ago> The old format $[expression] is deprecated and will be removed in upcoming versions of bash.