用于在 Ubuntu Xenial 上显示 CPU 信息、DDR、温度的 bash 脚本仅显示核心 3 信息

Question

我在带有 AllWinner H3 QuadCore Arm V7 的 Orange Pi 上运行 Ubuntu Xenial，需要不断监控 CPU 频率和温度，因此我有这个 bash 脚本来帮助我，但问题是它只显示核心 3 的信息，而不是其他的信息。

#/bin/bash
while (true); do
## retrieves core 0 info
    cpu0_cur=$(( `cat /sys/devices/system/cpu/cpu0/cpufreq/scaling_cur_freq` / 1000 ))
    cpu0_max=$(( `cat /sys/devices/system/cpu/cpu0/cpufreq/scaling_max_freq` / 1000 ))
    cpu0_min=$(( `cat /sys/devices/system/cpu/cpu0/cpufreq/scaling_min_freq` / 1000 ))
    cpu0_cur="$(printf "%4s" $cpu0_cur)"
    cpu0_max="$(printf "%4s" $cpu0_max)"
    cpu0_min="$(printf "%4s" $cpu0_min)"
## retrieves core 1 info
    cpu1_cur=$(( `cat /sys/devices/system/cpu/cpu1/cpufreq/scaling_cur_freq` / 1000 ))
    cpu1_max=$(( `cat /sys/devices/system/cpu/cpu1/cpufreq/scaling_max_freq` / 1000 ))
    cpu1_min=$(( `cat /sys/devices/system/cpu/cpu1/cpufreq/scaling_min_freq` / 1000 ))
    cpu1_cur="$(printf "%4s" $cpu1_cur)"
    cpu1_max="$(printf "%4s" $cpu1_max)"
    cpu1_min="$(printf "%4s" $cpu1_min)"
## retrieves core 2 info
    cpu2_cur=$(( `cat /sys/devices/system/cpu/cpu2/cpufreq/scaling_cur_freq` / 1000 ))
    cpu2_max=$(( `cat /sys/devices/system/cpu/cpu2/cpufreq/scaling_max_freq` / 1000 ))
    cpu2_min=$(( `cat /sys/devices/system/cpu/cpu2/cpufreq/scaling_min_freq` / 1000 ))
    cpu2_cur="$(printf "%4s" $cpu2_cur)"
    cpu2_max="$(printf "%4s" $cpu2_max)"
    cpu2_min="$(printf "%4s" $cpu2_min)"
## retrieves core 3 info
    cpu3_cur=$(( `cat /sys/devices/system/cpu/cpu3/cpufreq/scaling_cur_freq` / 1000 ))
    cpu3_max=$(( `cat /sys/devices/system/cpu/cpu3/cpufreq/scaling_max_freq` / 1000 ))
    cpu3_min=$(( `cat /sys/devices/system/cpu/cpu3/cpufreq/scaling_min_freq` / 1000 ))
    cpu3_cur="$(printf "%4s" $cpu3_cur)"
    cpu3_max="$(printf "%4s" $cpu3_max)"
    cpu3_min="$(printf "%4s" $cpu3_min)"
## retrieves system temp
    tempr=`cat /sys/devices/virtual/hwmon/hwmon1/temp1_input`
    tempr="$(printf "%3s" $tempr)"
## retrieves ddr info
    ddr_cur=$(( `cat /sys/devices/platform/sunxi-ddrfreq/devfreq/sunxi-ddrfreq/cur_freq` / 1000 ))
    ddr_max=$(( `cat /sys/devices/platform/sunxi-ddrfreq/devfreq/sunxi-ddrfreq/max_freq` / 1000 ))
    ddr_min=$(( `cat /sys/devices/platform/sunxi-ddrfreq/devfreq/sunxi-ddrfreq/min_freq` / 1000 ))
    ddr_cur="$(printf "%4s" $ddr_cur)"
    ddr_max="$(printf "%4s" $ddr_max)"
    ddr_min="$(printf "%4s" $ddr_min)"
## prints results
    echo -ne "  CORE 0 (MHz): $cpu0_cur (min $cpu0_min, max $cpu0_max)  TEMPERATURE: $tempr  MEMORY (MHz): $ddr_cur (min $ddr_min, max $ddr_max)   "\\r
    echo -ne "  CORE 1 (MHz): $cpu1_cur (min $cpu1_min, max $cpu1_max)  TEMPERATURE: $tempr  MEMORY (MHz): $ddr_cur (min $ddr_min, max $ddr_max)   "\\r
    echo -ne "  CORE 2 (MHz): $cpu2_cur (min $cpu2_min, max $cpu2_max)  TEMPERATURE: $tempr  MEMORY (MHz): $ddr_cur (min $ddr_min, max $ddr_max)   "\\r
    echo -ne "  CORE 3 (MHz): $cpu3_cur (min $cpu3_min, max $cpu3_max)  TEMPERATURE: $tempr  MEMORY (MHz): $ddr_cur (min $ddr_min, max $ddr_max)   "\\r
    sleep 0.2
done

但它的输出只是这样的：

CPU 3（MHz）：1536（最小480，最大1536）温度：74 内存（MHz）：672（最小408，最大672）

我已经记不太清楚 bash 脚本了，已经过去很多年了，不过请问一下我遗漏了什么？提前谢谢您 ;)

Answer 1

你有：

echo -ne "..."\\r

意思是：

• -n：不在末尾输出换行符，因此任何后续命令都从同一行开始
• -e：解释反斜杠转义序列，因此：
• \r变成回车，下一个命令从同一行的开头开始输出

因此，所有命令都会打印到同一行，每条命令都会覆盖前一条命令，并且只有最后一条命令可见。删除-ne和\r:

echo "  CORE 0 (MHz): $cpu0_cur (min $cpu0_min, max $cpu0_max)  TEMPERATURE: $tempr  MEMORY (MHz): $ddr_cur (min $ddr_min, max $ddr_max)   "

此外，您不需要所有这些变量：

while true; do
    tempr=$(cat /sys/devices/virtual/hwmon/hwmon1/temp1_input)
    ## retrieves ddr info
    ddr_cur=$(( $(cat /sys/devices/platform/sunxi-ddrfreq/devfreq/sunxi-ddrfreq/cur_freq) / 1000 ))
    ddr_max=$(( $(cat /sys/devices/platform/sunxi-ddrfreq/devfreq/sunxi-ddrfreq/max_freq) / 1000 ))
    ddr_min=$(( $(cat /sys/devices/platform/sunxi-ddrfreq/devfreq/sunxi-ddrfreq/min_freq) / 1000 ))
    for i in {0..3}; do
        ## retrieves core info
        cur=$(( $(cat /sys/devices/system/cpu/cpu$i/cpufreq/scaling_cur_freq) / 1000 ))
        max=$(( $(cat /sys/devices/system/cpu/cpu$i/cpufreq/scaling_max_freq) / 1000 ))
        min=$(( $(cat /sys/devices/system/cpu/cpu$i/cpufreq/scaling_min_freq) / 1000 ))
    ## retrieves system temp
        printf '\tCORE %d (MHz): %4s (min %4s, max %4s)  TEMPERATURE: %4s MEMORY (MHz): %4s(min %4s, max %4s)\n' $i "$cur" "$min" "$max" "$tempr" "$ddr_cur" "$ddr_min" "$ddr_max"
    done
    sleep 0.2
done