fix: [base] avoid appending new bits of code in ``~/.bash_profile``

This script was not idempotent, and that was an oversight.

precise/base-0k/hooks/install.d/30-customize.sh

@@ -18,13 +18,21 @@ parse_git_branch() {
 export PS1="\[\033[0;37m\][\[\033[1;30m\]\u\[\033[0;37m\]@\[\033[1;30m\]\H\[\033[0;37m\]]-[\[\033[1;34m\]\w\[\033[0;37m\]]\\\$(parse_git_branch)\n\[\033[1;37m\]\\$ \[\033[0;37m\]"
 EOF
 
-if [ -f /root/.bashrc.pre-install ]; then
-    cp /root/.bashrc.pre-install /root/.bashrc
-else
-    cp /root/.bashrc /root/.bashrc.pre-install
-fi
+protect_pre_install() {
+    local filename="$1"
+    if [ -f "$filename".pre-install ]; then
+        cp "$filename".pre-install "$filename"
+    else
+        if ! [ -e "$filename" ]; then
+            touch "$filename"
+        fi
+        cp "$filename" "$filename".pre-install
+    fi
+}
 
 
+protect_pre_install "/root/.bashrc"
+
 
 if ! type -p fzf; then
 
@@ -119,6 +127,9 @@ export FZF_CTRL_T_COMMAND="$FZF_DEFAULT_COMMAND"
 
 EOF
 
+
+protect_pre_install "/root/.bash_profile"
+
 cat <<EOF >> /root/.bash_profile
 
 ## XXXvlab: