interactive_echo() {
  case "$-" in
    *i*) echo $*
  esac
}

remove_path() {
  cur_idx=$path[(i)$1]
  while (( $cur_idx <= $#path )); do
    path[$cur_idx]=()
    cur_idx=$path[(i)$1]
  done
}

add_exe_path() {
  remove_path "$1"
  if [[ -d $1 ]]; then
    path+=("$@")
  fi
}

push_exe_path() {
  remove_path "$1"
  if [[ -d $1 ]]; then
    while (( idx = $path[(Ie)$1] )); do
      path[$idx]=()
    done
    path+=("$@")
  fi
}

prepend_exe_path() {
  remove_path "$1"
  if [[ -d $1 ]]; then
    while (( idx = $path[(Ie)$1] )); do
      path[$idx]=()
    done
    path[1]=("$1" "$path[1]")
  fi
}

mkcd() {
  mkdir "$@"
  cd "$1"
}

dupfind() {
  local parallel
  parallel="$(command -v parallel)"
  parallel="${parallel:-$(command -v xargs)}"

  local dir
  dir="${1:-.}"
  find "$dir" \( \( -name .git -o -name CVS \) -prune \) -o  \( -type f \) -print0  |
    $parallel -0 shasum |
    sort |
    ${GNU_PREFIX}uniq -w 20 -c |
    sort -nr
}

is-function () {
  whence -w $1 | grep -I function > /dev/null
}

is-alias () {
  whence -w $1 | grep -I alias > /dev/null
}

expand-alias () {
  local POSSIBLE_ALIAS
  if [[ ! -z "$1" ]]; then
    POSSIBLE_ALIAS="$(alias $1)"
    if [[ ! -z "$POSSIBLE_ALIAS" ]]; then
      echo "${POSSIBLE_ALIAS#*=}"
    else
      echo "$1"
    fi
  fi
}

truncfile() {
    echo $1
    (( number = $1 - 1 ))
    ${GNU_PREFIX}sed -i "${number}q" $2
}