diff --git a/harpoon b/harpoon
index e66ba53..a74c560 100755
--- a/harpoon
+++ b/harpoon
@@ -19,7 +19,9 @@ help() {
     echo "Options:"
     echo "    -a                    Track current tmux session"
     echo "    -A                    Track pane within current tmux session"
-    echo "    -r [session_name]     Stop tracking session with session name. If"
+    echo "    -r [index]            Replace tracked entry at index with current session"
+    echo "    -R [index]            Replace tracked entry at index with current pane within session"
+    echo "    -d [session_name]     Stop tracking session with session name. If"
     echo "                          session_name is not passed then remove current session"
     echo "    -l                    List tracked sessions"
     echo "    -s [index]            Switch to the session at the specified index in the"
@@ -47,12 +49,39 @@ view() {
     _switch "$name" "$path"
 }
 
-add() {
-    extended="$1"
+_getBookmark() {
+    extended=$1
+
     base_info='#{session_name}=#{session_path}'
     pane_info=':#{window_index}.#{pane_index}'
-    tmux display -p "$base_info$([ "$extended" = 1 ] && echo "$pane_info")" >>"$cachefile"
+    tmux display -p "$base_info$([ "$extended" = true ] && echo "$pane_info")"
+}
+
+_dedupe() {
     awk -i inplace '!seen[$0]++' "$cachefile" # de-duplicate
+}
+
+replace() {
+    bookmark=$(_getBookmark "$1")
+    index=$2
+
+    linenumbers=$(wc -l <"$cachefile")
+    if [ "$linenumbers" -gt "$index" ]; then
+        escaped_bookmark=$(echo "$bookmark" | sed 's/\//\\\//g')
+        sed -i "${index}s/.*/$escaped_bookmark/" "$cachefile"
+    else
+        echo "$bookmark" >>"$cachefile"
+    fi
+
+    _dedupe
+    exec tmux display "Tracking session #{session_name} in index $index"
+}
+
+add() {
+    bookmark=$(_getBookmark "$1")
+
+    echo "$bookmark" >>"$cachefile"
+    _dedupe
     exec tmux display 'Tracking session #{session_name}'
 }
 
@@ -90,12 +119,14 @@ list_sessions() { tmux ls -F '#{session_name}=#{session_path}'; }
 bold() { printf "\033[1m%s\033[0m\n" "$*"; }
 
 main() {
-    while getopts ":haAr:ls:e" opt; do
+    while getopts ":haAr:R:d:ls:e" opt; do
         case "$opt" in
         h | :) help && exit 0 ;;
-        a) add ;;
-        A) add 1 ;;
-        r) remove "$OPTARG" ;;
+        a) add false ;;
+        A) add true ;;
+        r) replace false "$OPTARG" ;;
+        R) replace true "$OPTARG" ;;
+        d) remove "$OPTARG" ;;
         l) view ;;
         s) switch "$OPTARG" ;;
         e) edit_file ;;
diff --git a/readme.md b/readme.md
index 00266c9..8f19331 100644
--- a/readme.md
+++ b/readme.md
@@ -23,7 +23,9 @@ Usage:
 Options:
     -a                    Track current tmux session
     -A                    Track pane within current tmux session
-    -r [session_name]     Stop tracking session with session name. If
+    -r [index]            Replace tracked entry at index with current session
+    -R [index]            Replace tracked entry at index with current pane within session
+    -d [session_name]     Stop tracking session with session name. If
                           session_name is not passed then remove current session
     -l                    List tracked sessions
     -s [index]            Switch to the session at the specified index in the
@@ -42,10 +44,14 @@ bind -n M-b run 'harpoon -a'
 bind -n .   run 'harpoon -A'
 bind -n M-v run 'harpoon -l'
 bind -n M-i run 'harpoon -e'
-bind -n M-n run 'harpoon -s 1'
-bind -n M-e run 'harpoon -s 2'
-bind -n M-o run 'harpoon -s 3'
-bind -n M-s run 'harpoon -s 4'
+bind -n M-q run 'harpoon -s 1'  # alt+q goes to index 1
+bind M-q run 'harpoon -r 1'     # prefix alt+q replace entry index 1 with current session
+bind -n M-w run 'harpoon -s 2'
+bind M-w run 'harpoon -R 2'     # replace entry at index 2 with current pane within session
+bind -n M-e run 'harpoon -s 3'
+bind -n M-r run 'harpoon -s 4'
+
+# Note: If there is no entry at the given index, it is appended to the list instead.# adds pane instead of session to index 2
 ```
 
 ## Example