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

     path+=("$@")

   fi

 }
 
 prepend_exe_path() {

   remove_path "$1"

   if [[ -d $1 ]]; then

     path[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
 }