shell/fzf: improve fzf-apps + scratch terminal integration + refactor

shell/fzf/bin/fzf-apps

@@ -12,6 +12,9 @@ case $OSTYPE in
     linux*)
         cmd=$(echo -n "$PATH" | xargs -d: -I{} -r -- find -L {} -maxdepth 1 -mindepth 1 -type f -executable -printf '%P\n' 2>/dev/null | sort -u | gui-fzf)
         if [[ $cmd ]]; then
+            if [[ $cmd == fzf-* ]]; then
+                $cmd
+            else
                 if ! which lnch >/dev/null; then
                     notify-send 'lnch is not installed' 'run "go get github.com/oem/lnch"'
                     exit 1
@@ -19,10 +22,13 @@ case $OSTYPE in
 
                 # This disowns the subprocess from the parent shell (i.e. if
                 # that shell gets closed, the subprocess will survive).
-            if [[ $cmd == fzf-* ]]; then
-                $cmd
-            else
                 lnch "$cmd"
+
+                # OPTIONAL: requires bin/tmux
+                if command -v 'tmux-session-name' >/dev/null; then
+                    # If this was used from a scratch tmux terminal, close it
+                    [[ "$(tmux-session-name)" == scratch ]] && tmux kill-session -t scratch
+                fi
             fi
         fi
         ;;