BASH - 字符串输出不是我所期望的

Question

我有需要回应的情况：

变量 - 纯文本 - 函数调用的结果

我很困惑呼应时各种符号的含义

这是我的功能：

#!/bin/bash

getLogTimestamp() {
    echo $(date +%Y-%m-%dT%H:%M:%S.130Z)
}

getDisplayName(){
echo $(awk -F'=' '/^CARBON_LITE_PLAYER_ID=.*/ { print $2;}' /home/benja/app/.env)
}

getDeviceIPAddress(){
echo $(hostname -i)
}

getSystemUptime(){
echo $(uptime)
}

getDateTimeInfo(){
echo "$(timedatectl status | awk '/Warning/{exit} 1')"
}

getMemoryInfo() {
    arr=( $(free -h) )
    keys=("${arr[@]::8}")
    vals=("${arr[@]:8:12}")
    for i in ${!keys[@]}; { printf -v data[i] "%s: %s, " "${keys[i]}" "${vals[i]}"; }
    data="${data[@]}"
    echo ${data%,*}
}

getDiskInfo()
{
  arr=($(df -h))
    keys=("${arr[@]::6}")
    vals=("${arr[@]:7:100}")
    for i in ${!keys[@]}; { printf -v data[i] "%s: %s, " "${keys[i]}" "${vals[i]}"; }
    data="${data[@]}"
    echo ${data%,*}
}

getDisplayState(){
    STATE=$(/opt/vc/bin/tvservice -s | awk '/state/  {print $2}')

    case $STATE in

    $STATE=0x40001 )
            echo VC_SDTV_NTSC, VC_HDMI_UNPLUGGED 
            ;;
    $STATE=0x40002 )
            echo VC_SDTV_NTSC, VC_HDMI_ATTACHED
            ;;
    $STATE=0x120002 )
            echo VC_SDTV_ATTACHED, VC_SDTV_CP_INACTIVE, VC_HDMI_ATTACHED
            ;;
    $STATE=0x120005 )
            echo VC_SDTV_ATTACHED, VC_SDTV_CP_INACTIVE, VC_HDMI_UNPLUGGED, VC_HDMI_DVI
            ;;
    $STATE=0x120016 )
            echo VC_SDTV_ATTACHED, VC_SDTV_CP_INACTIVE, VC_HDMI_ATTACHED, VC_HDMI_DVI, VC_HDMI_HDCP_UNAUTH
            ;;
    $STATE=0x12001a )
            echo VC_SDTV_ATTACHED, VC_SDTV_CP_INACTIVE, VC_HDMI_ATTACHED, VC_HDMI_HDMI, VC_HDMI_HDCP_UNAUTH
            ;;
    $STATE=0x12001a )
            echo VC_SDTV_ATTACHED, VC_SDTV_CP_INACTIVE, VC_HDMI_ATTACHED, VC_HDMI_HDMI
            ;;
    $STATE=0x120009 )
            echo  VC_SDTV_ATTACHED, VC_SDTV_CP_INACTIVE, VC_HDMI_UNPLUGGED, VC_HDMI_HDMI
            ;;
    esac
}

在一个单独的文件中，我调用了这些函数：

#Logging
. /home/benja/app/scripts/log-helper-functions.sh
LOGTIMESTAMP=getLogTimestamp

# RSH -We are logging this data every time this script runs (chron job)

echo $LOGTIMESTAMP "Display Name: $(getDisplayName)"

echo $LOGTIMESTAMP "Device IP: $(getDeviceIPAddress)"

echo $LOGTIMESTAMP "System UpTime: $(getSystemUptime)"

echo $LOGTIMESTAMP "DateTime Info: $(getDateTimeInfo)"

echo $LOGTIMESTAMP "Memory Info: $(getMemoryInfo)"

echo $LOGTIMESTAMP "Disk Info: $(getDiskInfo)"

echo $LOGTIMESTAMP "Display State: $(getDisplayState)"

# RSH end

这是一个输出示例：

getLogTimestamp Display Name: UAT-101429
getLogTimestamp Device IP: 10.0.0.120
getLogTimestamp System UpTime: 23:26:06 up 19:54, 1 user, load average: 1.66, 0.82, 0.47
getLogTimestamp DateTime Info:       Local time: Thu 2020-04-09 23:26:06 EDT
  Universal time: Fri 2020-04-10 03:26:06 UTC
        RTC time: n/a
       Time zone: America/New_York (EDT, -0400)
 Network time on: yes
NTP synchronized: no
 RTC in local TZ: yes
getLogTimestamp Memory Info: total: 174M, used: 42M, free: 91M, shared: 388M, buff/cache: 317M, available: Swap:, Mem:: 0B, 605M: 0B
getLogTimestamp Disk Info: Filesystem: /dev/root, Size: 30G, Used: 4.6G, Avail: 23G, Use%: 17%, Mounted: /
getLogTimestamp Display State: 

问题：显然 $TIMESTAMP 没有解析，Display State 也没有解析。

我做错了什么？

TIA -罗恩

Answer 1

作业的右侧通常不会运行。您需要告诉 bash 运行它并使用输出：

LOGTIMESTAMP=$(getLogTimestamp)

case 语句具有不同的语法。每个案例只包含值，您已经在case $STATE 行中声明了$STATE，无需在每一行重复。

case "$STATE" of
    0x40001) ...