diff --git a/bin/gen_list.sh b/bin/gen_list.sh
new file mode 100755
index 0000000..2fc5875
--- /dev/null
+++ b/bin/gen_list.sh
@@ -0,0 +1,131 @@
+#!/bin/bash
+
+# This file contains list-manipulation functions.
+
+# A list is defined here as a string of items separated by some delimiter.
+# The PATH variable is one such example.
+
+if ! test "${default_delim+defined}" ; then
+  readonly default_delim=" "
+fi
+
+# Performance note:  It is important for these functions to run quickly.  One
+# way to increase their speed is to avoid copying function arguments to local
+# variables and to instead use numbered arguments (e.g. ${1}, {2}, etc.) to
+# access the arguments from inside the functions.  In some trials, this
+# doubled the speed of the functions.  The cost of this is that it makes the
+# functions slightly more difficult to read.
+
+
+function add_list_element {
+  # local list_element="${1}"
+  # local list_name="${2}"
+  # local delim="${3:-${default_delim}}"
+  # local position="${4:-back}"
+
+  # Add the list_element to the list named in list_name.
+
+  # Description of argument(s):
+  # list_element                    The list element to be added.
+  # list_name                       The name of the list to be modified.
+  # delim                           The delimiter used to separate list
+  #                                 elements.
+  # position                        Indicates the position in the list where
+  #                                 the new element should be added
+  #                                 ("front"/"back").
+
+  if [ -z "${!2}" ] ; then
+    # The list is blank. Simply assign it the list_element value and return.
+    eval "${2}=\"${1}\""
+    return
+  fi
+
+  if [ "${4:-back}" == "back" ] ; then
+    # Append the list_element to the back of the list and return.
+    eval "${2}=\"\${${2}}\${3-${default_delim}}\${1}\""
+    return
+  fi
+
+  # Append the list_element to the front of the list and return.
+  eval "${2}=\"\${1}\${3-${default_delim}}\${${2}}\""
+
+}
+
+
+function remove_list_element {
+  # local list_element="${1}"
+  # local list_name="${2}"
+  local delim="${3:-${default_delim}}"
+
+  # Remove all occurrences of list_element from the list named in list_name.
+
+  # Description of argument(s):
+  # list_element                    The list element to be removed.
+  # list_name                       The name of the list to be modified.
+  # delim                           The delimiter used to separate list
+  #                                 elements.
+
+  local __rle_new_list__="${!2}"
+
+  # Special case: The list contains one element which matches the specified
+  # list element:
+  if [ "${1}" == "${__rle_new_list__}" ] ; then
+    eval ${2}=\"\"
+    return
+  fi
+
+  # Replace all occurrences of list_element that are bounded by the delimiter
+  # on both sides.
+  __rle_new_list__="${__rle_new_list__//${delim}${1}${delim}/${delim}}"
+  # Replace list_item if it occurs at the beginning of the string and is
+  # bounded on the right by the delimiter.
+  __rle_new_list__="${__rle_new_list__#${1}${delim}}"
+  # Replace list_item if it occurs at the end of the string and is bounded on
+  # the left by the delimiter.
+  __rle_new_list__="${__rle_new_list__%${delim}${1}}"
+
+  # Set caller's variable to new value.
+  eval ${2}=\"\${__rle_new_list__}\"
+
+}
+
+
+function cleanup_path_slashes {
+  local var_name="${1}" ; shift
+
+  # For the variable named in var_name, replace all multiple-slashes with
+  # single slashes and strip any trailing slash.
+
+  # Description of argument(s):
+  # var_name                        The name of the variable whose contents
+  #                                 are to be changed.
+
+  local cmd_buf
+
+  cmd_buf="${var_name}=\$(echo \"\${${var_name}}\" | sed -re 's#[/]+#/#g' -e 's#/\$##g')"
+  eval "${cmd_buf}"
+
+}
+
+
+function remove_path {
+  local dir_path="${1}" ; shift
+  local path_var="${1:-PATH}" ; shift
+
+  # Remove all occurrences of dir_path from the path variable named in
+  # path_var.
+
+  # Note that this function will remove extraneous slashes from the elements
+  # of path_var.
+
+  # Description of argument(s):
+  # dir_path                        The directory to be removed from the path
+  #                                 variable.
+  # path_var                        The name of a variable containing
+  #                                 directory paths separated by colons.
+
+  cleanup_path_slashes dir_path || return 1
+  cleanup_path_slashes ${path_var} || return 1
+  remove_list_element "${dir_path}" "${path_var}" : || return 1
+
+}