Add prepend() to simplify mass-renaming files by prepending a string

(Yeah, I know, weirdly specific and likely not very useful.)

dotfiles/config/bashum/main.bashrc

 ### SUBZ ###
 ### '''' ###
 
+prepend() {
+    #
+    # pre-pend $2 to filename $1
+    #
+    local path=$1
+    local prefix=$2
+    local dirpath
+    local filename
+    local abspath
+    abspath=$(readlink -f "$path")
+    dirpath=$(dirname "$abspath")
+    filename=$(basename "$abspath")
+    echo mv "$path" "$dirpath/$prefix-$filename"
+}
+
 smv() {
     #
     # scp but rm the source