Updates for profile and bashrc; PS1 simplification

EtcFiles/profile

@@ -3,9 +3,30 @@
 #Set our umask
 umask 022
 
-# Set our default path
-PATH="/usr/local/sbin:/usr/local/bin:/usr/sbin:/usr/bin:/sbin:/bin:~/bin"
+# Append "$1" to $PATH when not already in.
+# This function API is accessible to scripts in /etc/profile.d
+append_path () {
+    case ":$PATH:" in
+        *:"$1":*)
+            ;;
+        *)
+            PATH="${PATH:+$PATH:}$1"
+    esac
+}
+
+# Append our default paths
+append_path '/usr/local/sbin'
+append_path '/usr/local/bin'
+append_path '/usr/sbin'
+append_path '/usr/bin'
+append_path '/sbin'
+append_path '/bin'
+append_path '~/bin'
+
+# Force PATH to be environment
 export PATH
+
+# Set IFS to be newline delimited
 IFS="
 "
 export IFS
@@ -18,8 +39,16 @@ if test -d /etc/profile.d/; then
 	unset profile
 fi
 
-# Source global bash config
-if test "$PS1" && test "$BASH" && test -r /etc/bashrc; then
+# Unload our profile API functions
+unset -f append_path
+
+# Source global bash config, when interactive but not posix or sh mode
+if test "$BASH" &&\
+   test "$PS1" &&\
+   test -z "$POSIXLY_CORRECT" &&\
+   test "${0#-}" != sh &&\
+   test -r /etc/bashrc
+then
 	. /etc/bashrc
 fi
 
@@ -28,5 +57,3 @@ unset TERMCAP
 
 # Man is much better than us at figuring this out
 unset MANPATH
-
-