I use `set -e` but it has its own quirks. A couple:

An arithmetic expression that evaluates to zero will cause the script to exit. e.g this will exit:

  set -e
  i=0
  (( i++ )) # exits

Calling a function from a conditional prevents `set -e` from exiting. The following prints "hello\nworld\n":

  set -e
  main() {
     false  # does not return nor exit
     echo hello
  }
  if main; then echo world; fi

Practically speaking this means you need to explicitly check the return value of every command you run that you care about and guard against `set -e` in places you don't want the script to exit. So the value of `set -e` is limited.

More at https://mywiki.wooledge.org/BashFAQ/105

grep has a bad interaction with set -e, since it (infuriatingly) exits with 1 if no lines are matched.