bash/ksh function to add an entry to the head or tail of a path. Existing duplicate entries are removed.

add_to_path.sh

function add_to_path
{
   # Adds an entry to the path (adds to the head by default).
   # If the entry already exists, it is removed from its current location
   # and added to the tail or head, as specified.
   # Duplicate entries are removed.
   # Examples: PATH=$(add_to_path $PATH /path/to/add head)
   #           LD_LIBRARY_PATH=$(add_to_path $LD_LIBRARY_PATH /path/to/add)
   NEW=$(echo $1 | /bin/awk -F':' -vADD=$2 -vLOC=$3 'BEGIN {new=""}
          {for (i=1;i<=NF;i++) {if ($i!=ADD)
              {if (new=="") {new=$i} else {new=sprintf("%s:%s",new,$i)}}}}
          END {if ($0=="") {print ADD}
               else {if (LOC=="tail") {printf("%s:%s",new,ADD)}
                     else {printf("%s:%s",ADD,new)}}}')
   echo $NEW
}