yank.sh. Use netstat instead of ss as more compatible solution

install.sh

@@ -1,4 +1,4 @@
-#!/bin/bash
+#!/usr/bin/env bash
 
 set -e
 set -u

readme.md

@@ -52,7 +52,7 @@ Installation
 -------------
 Prerequisites:
 - tmux >= "v2.4"
-- OSX, Linux (tested on Ubuntu 14 and CentOS7)
+- OSX, Linux (tested on Ubuntu 14 and CentOS7), FreeBSD (tested on 11.1)
 
 Personally, I use it on OSX 10.11.5 El Capitan through iTerm2.
 

tmux/renew_env.sh

@@ -1,4 +1,4 @@
-#!/bin/bash
+#!/usr/bin/env bash
 
 set -eu
 

tmux/yank.sh

@@ -1,4 +1,4 @@
-#!/bin/bash
+#!/usr/bin/env bash
 
 set -eu
 
@@ -22,7 +22,9 @@ elif [ -n "${DISPLAY-}" ] && is_app_installed xsel; then
  copy_backend="xsel -i --clipboard"
 elif [ -n "${DISPLAY-}" ] && is_app_installed xclip; then
  copy_backend="xclip -i -f -selection primary | xclip -i -selection clipboard"
-elif [ -n "${copy_backend_remote_tunnel_port-}" ] && [ "$(ss -n -4 state listening "( sport = $copy_backend_remote_tunnel_port )" | tail -n +2 | wc -l)" -eq 1 ]; then
+elif [ -n "${copy_backend_remote_tunnel_port-}" ] \
+ && (netstat -f inet -nl 2>/dev/null || netstat -4 -nl 2>/dev/null) \
+ | grep -q "[.:]$copy_backend_remote_tunnel_port"; then
  copy_backend="nc localhost $copy_backend_remote_tunnel_port"
 fi