set -f path=("/new/entry" $path:q)

set -f path=('/new/'e"ntry" $path:q)

set -f path=(/'new/entry' $path:q)

set path=(/new/entry $path:q)
set -f path=($path:q)

if ( $PATH =~ */some/path* ) then
    set PATH = ($PATH:/some/path)
endif

UNIQUE_LIST=$( echo "$PATH" | tr ':' 'n' | sort | uniq)

# then we place in front those from UNIQUELIST that match an ordered list
# note that that way, those who didn't have "/sbin" still won't have it, but if they did
# it will be at the right place in the list
shouldbefirst="/bin /sbin /usr/bin" # complete or re-order as needed on your system...
for dir in $shouldbefirst
do
   if ( echo "$UNIQUE_LIST" | grep "$dir" >/dev/null 2>/dev/null)
   then #we have this dir in UNIQUE_LIST
      NEWLIST="${NEWLIST}:${dir}"
      UNIQUE_LIST="$( echo "$UNIQUE_LIST" | grep -v "^$dir$")"  #we treated that one, take it out of the original list
   fi
done

# then put the remaining of UNIQUE_LIST in the order you want (here, alphabetically)
for dir in $UNIQUE_LIST
do
   NEWLIST="${NEWLIST}:${dir}"
   UNIQUE_LIST="$( echo "$UNIQUE_LIST" | grep -v "^$dir$")"  #we treated that one, take it out of the original list
done

 # get rid of possible first ":" (as NEWLIST starts empty)
 NEWLIST="$(echo "$NEWLIST" | sed -e 's/^://')"

 # and then : (I test by placing "echo" in front, get rid of "echo" if it looks fine)
 echo PATH="$NEWLIST"