Reverse `find`

In the last few days I discovered I needed to search back up the filesystem from $CWD to find the first occurence of a file (specifically, a Justfile but that’s by-the-by). Got bored of doing it by hand so wrote a bash shell function; here ’tis:

rf () {
  local D
  while ! eza -l "${D:=.}/$1"; do               # first, check `$CWD`
    [ "$(realpath "$D/$1")" == "/$1" ] && break # stop if we hit `/` already
    D=$D/..                                     # else, iterate one layer up
  done
}

Invoke as (e.g.,) rf Justfile. Alternatively, as a one-liner:

F=Justfile; while ! eza -l ${D:=.}/$F; do [ "$(realpath $D/$F)" == "/$F" ] && break; D=$D/..; done; unset D