<sdomi>
you can even do array accesses in there, i.e. `echo "${b:arr[1]:1}"`
<sdomi>
s/:c:c/:a:a/ my bad
<sdomi>
unfortunately, you can't do a string slice within a string slice, beyond "${b:${a:1:1}:1}" (but that requires the dollar for expansion, it's boring)
<sdomi>
another cool hack: `${b::1}` implies the 0th letter
<sdomi>
`${b:0:5}` -> asdfa
<sdomi>
`${b:-1:5}` -> asdfasdf
<sdomi>
`${b:0-2:2}` -> df (the last one)
<sdomi>
anyways i'm semi-surprised that this is yet another place where you can do math
<isabella>
${b:-1:5} is expanded as ${var:-fallback}
<isabella>
you want ${b: -1:5}
<isabella>
${var:-fallback} == $var if it's not empty, otherwise fallback
<isabella>
so in your case it just expanded $var
<sdomi>
isabella: oh, indeed
<sdomi>
tbh i prefer the `${b:0-1:5}` syntax, looks less like a typo XD