bash: use addpath to only add paths once

bashrc

@@ -5,6 +5,21 @@
 # If not running interactively, don't do anything
 [ -z "$PS1" ] && return
 
+# Add an entry to PATH, iff it's not already there.
+addpath() {
+    wanted_path=$1
+    at_end=$2
+    FOUND=$(echo $PATH | grep $wanted_path)
+    if [ $? -ne 0 ] ; then
+        echo "Found with grep"
+        if [ "$at_end" == "" ] ; then
+            export PATH=$wanted_path:$PATH
+        else
+            export PATH=$PATH:$wanted_path
+        fi
+    fi
+}
+
 # don't put duplicate lines in the history. See bash(1) for more options
 # don't overwrite GNU Midnight Commander's setting of `ignorespace'.
 export HISTCONTROL=$HISTCONTROL${HISTCONTROL+,}ignoredups
@@ -69,7 +84,9 @@ xterm*|rxvt*)
 esac
 export PROMPT_DIRTRIM=3
 
-export PATH=$HOME/bin:$PATH:$HOME/opt/bin
+addpath $HOME/bin
+addpath $HOME/opt/bin end
+
 export IPLAYER_OUTDIR="$HOME/downloads/iplayer"
 
 # enable color support of ls and also add handy aliases
@@ -123,8 +140,6 @@ fi
     # echo "Note - Dropbox isn't running!"
 # fi
 
-export PATH=$HOME/bin:$PATH
-
 [ -f ~/.fzf.bash ] && source ~/.fzf.bash
 
 # Load any supplementary scripts