优化：改用脚本显示网速

mux_net_speed.sh

@@ -0,0 +1,16 @@
+#!/bin/bash
+IF=wlp3s0
+TMPFILE=/tmp/tmux_net_speed.txt
+
+# 初始化上一秒流量
+read RX_PREV TX_PREV <<< $(awk -v iface=$IF '$1 ~ iface {print $2, $10}' /proc/net/dev)
+
+while true; do
+    sleep 1
+    read RX_CUR TX_CUR <<< $(awk -v iface=$IF '$1 ~ iface {print $2, $10}' /proc/net/dev)
+    RX_RATE=$(( (RX_CUR - RX_PREV)/1024 ))
+    TX_RATE=$(( (TX_CUR - TX_PREV)/1024 ))
+    printf "↑%dKB/s ↓%dKB/s" $TX_RATE $RX_RATE > $TMPFILE
+    RX_PREV=$RX_CUR
+    TX_PREV=$TX_CUR
+done