In the wiredtiger code repository, there are some shell scripts (e.g. dist/s_all) that are set to call system shell (#!/bin/sh), which could be "translated" into varied types of shells in different OS systems/distributions, e.g. bash, dash, zsh. Having a way to check shell changes being portable across different types of shells before code merge is useful to avoid portability issues being introduced into our code base, affecting users of one particular or certain types of shells. 

shellcheck has a "portability" feature that seems relevant. We can explore other tools as well.