[Help-bash] cd command completion from a numerical number to ../{n}?

[Peng Yu]

Hi,

When I type 'cd 2'<TAB>, I want to expand it to 'cd ../../' where 2
determines the number of '../'. When it is not a number of cd, I want
the completion be done as the default. I came up with the following
solution. Is it the best one?

_cd_command() {
  local i="$2"
  if [[ "$i" =~ [0-9]+ ]]
  then
    unset COMPREPLY
    while [ "$i" -ne 0 ]
    do
      COMPREPLY=../$COMPREPLY
      ((i=i-1))
    done
  else
    COMPREPLY=("$i"*/)
    if [ ! -e "$COMPREPLY" ]
    then
      unset COMPREPLY
    else
      COMPREPLY=("address@hidden/}")
    fi
  fi
}

complete -F _cd_command -o nospace -o filenames cd

Regards,
Peng