Support updating PATH in place

`path_prepend` and `path_append` would previously only add a directory
if it wasn't already in the PATH. Now it will move the directory to
the start/end. This allows the PATH to be adjusted more readily.

etc/bash/defaults/00.path.sh

@@ -2,10 +2,11 @@
 #
 # Set the default PATH.
 
-path_append '/sbin'
-path_append '/bin'
-path_append '/usr/sbin'
-path_append '/usr/bin'
-path_append '/usr/local/bin'
-path_append '/usr/local/sbin'
-path_prepend "${HOME}/bin"
+path_append /usr/local/bin
+path_append /usr/local/sbin
+path_append /usr/bin
+path_append /bin
+path_append /usr/sbin
+path_append /sbin
+
+path_prepend ${HOME}/bin

etc/bash/functions/00.flags.sh

@@ -14,6 +14,9 @@ fi
 # The current Operating System type (eg. Linux, Darwin, NetBSD)
 export HOSTOS=`uname`
 
+# The current machine architecture
+export HOSTARCH=`uname -m`
+
 # The current host's name, in short form (without domain name).
 export HOST=`hostname -s`
 

etc/bash/functions/00.path.sh

@@ -2,24 +2,28 @@
 #
 # Easily extending the PATH and MANPATH.
 
+function strip_path_dir {
+    local directory="$1"
+
+    echo "$PATH" \
+        | sed -e 's/:/\n/g' \
+        | grep -v "^${directory}\$" \
+        | tr '\n' ':' \
+        | sed -e 's/:$//'
+}
+
 function path_append {
     local directory="$1"
-
-    if [ -x "$directory" ]; then
-        echo "$PATH" | grep "$directory" &> /dev/null
-        [ $? -eq 1 ] \
-            && PATH="${PATH}:${directory}"
-    fi
+
+    [ -x "$directory" ] \
+        && PATH="$(strip_path_dir "$directory"):$directory"
 }
 
 function path_prepend {
     local directory="$1"
 
-    if [ -x "$directory" ]; then
-        echo "$PATH" | grep "$directory" &> /dev/null
-        [ $? -eq 1 ] \
-            && PATH="${directory}:${PATH}"
-    fi
+    [ -x "$directory" ] \
+        && PATH="$directory:$(strip_path_dir "$directory")"
 }
 
 function manpath_append {

etc/bash/functions/20.source.sh

@@ -31,6 +31,7 @@ function source_init_tree {
 
     source_if_exists ${dir}/*.sh
     source_if_exists ${dir}/os-${HOSTOS}/*.sh
+    source_if_exists ${dir}/os-${HOSTOS}-${HOSTARCH}/*.sh
     source_if_exists ${dir}/arch-${HOSTTYPE}/*.sh
     source_if_exists ${dir}/domain-${DOMAIN}/*.sh
     source_if_exists ${dir}/host-${HOST}/*.sh