Armbian欢迎信息系统状态脚本

代码

从/etc/update-motd.d/30-armbian-sysinfo提取，
涉及shell字符串提取非常具有参考价值，源码如下：

#!/bin/bash
#
# Copyright (c) Authors: http://www.armbian.com/authors
#
# This file is licensed under the terms of the GNU General Public
# License version 2. This program is licensed "as is" without any
# warranty of any kind, whether express or implied.
#

# DO NOT EDIT THIS FILE but add config options to /etc/default/armbian-motd
# generate system information

export PATH=/usr/local/sbin:/usr/local/bin:/usr/sbin:/usr/bin:/sbin:/bin

THIS_SCRIPT="sysinfo"
MOTD_DISABLE=""
STORAGE=/dev/sda1
SHOW_IP_PATTERN="^[ewr].*|^br.*|^lt.*|^umts.*"

[[ -f /etc/default/armbian-motd ]] && . /etc/default/armbian-motd

for f in $MOTD_DISABLE; do
	[[ $f == $THIS_SCRIPT ]] && exit 0
done

# don't edit below here

function display() {
	# $1=name $2=value $3=red_limit $4=minimal_show_limit $5=unit $6=after $7=acs/desc{
	# battery red color is opposite, lower number
	if [[ "$1" == "Battery" ]]; then local great="<"; else local great=">"; fi
	if [[ -n "$2" && "$2" > "0" && (( "${2%.*}" -ge "$4" )) ]]; then
	printf "%-14s%s" "$1:"
		if awk "BEGIN{exit ! ($2 $great $3)}"; then echo -ne "e[0;91m $2"; else echo -ne "e[0;92m $2"; fi
		printf "%-1s%sx1B[0m" "$5"
		printf "%-11s%s	" "$6"
		return 1
	fi
} # display

function getboardtemp() {
	if [ -f /etc/armbianmonitor/datasources/soctemp ]; then
		read raw_temp </etc/armbianmonitor/datasources/soctemp 2>/dev/null
		if [ ! -z $(echo "$raw_temp" | grep -o "^[1-9][0-9]*.?[0-9]*$") ] && (( $(echo "${raw_temp} < 200" |bc -l) )); then
			# Allwinner legacy kernels output degree C
			board_temp=${raw_temp}
		else
			# Marvell gets special treatment for whatever reasons
			grep -qi Marvell /proc/cpuinfo && 
				board_temp=$(( $(awk '{printf("%d",$1/1000)}' <<<${raw_temp}) - 20 )) || 
				board_temp=$(awk '{printf("%d",$1/1000)}' <<<${raw_temp})
		fi
	elif [ -f /etc/armbianmonitor/datasources/pmictemp ]; then
		# fallback to PMIC temperature
		board_temp=$(awk '{printf("%d",$1/1000)}' </etc/armbianmonitor/datasources/pmictemp)
	fi
} # getboardtemp

function batteryinfo() {
	# Battery info for Allwinner
	mainline_dir="/sys/power/axp_pmu"
	legacy_dir="/sys/class/power_supply"
	if [[ -e "$mainline_dir" ]]; then
		read status_battery_connected < $mainline_dir/battery/connected
		if [[ "$status_battery_connected" == "1" ]]; then
			read status_battery_charging < $mainline_dir/charger/charging
			read status_ac_connect < $mainline_dir/ac/connected
			read battery_percent< $mainline_dir/battery/capacity
			# dispay charging / percentage
			if [[ "$status_ac_connect" == "1" && "$battery_percent" -lt "100" ]]; then
				status_battery_text=" charging"
			elif [[ "$status_ac_connect" == "1" && "$battery_percent" -eq "100" ]]; then
				status_battery_text=" charged"
			else
				status_battery_text=" discharging"
			fi
		fi
	elif [[ -e "$legacy_dir/axp813-ac" ]]; then
		read status_battery_connected < $legacy_dir/axp20x-battery/present
		if [[ "$status_battery_connected" == "1" ]]; then
			status_battery_text=" "$(awk '{print tolower($0)}' < $legacy_dir/axp20x-battery/status)
	                read status_ac_connect < $legacy_dir/axp813-ac/present
	                read battery_percent< $legacy_dir/axp20x-battery/capacity
		fi
	elif [[ -e "$legacy_dir/battery" ]]; then
		if [[ (("$(cat $legacy_dir/battery/voltage_now)" -gt "5" )) ]]; then
			status_battery_text=" "$(awk '{print tolower($0)}' < $legacy_dir/battery/status)
			read battery_percent <$legacy_dir/battery/capacity
		fi
	fi
} # batteryinfo

function ambienttemp() {
	# read ambient temperature from USB device if available
	if [[ ! -f /usr/bin/temper ]]; then
		echo ""
		return
	fi
	amb_temp=$(temper -c 2>/dev/null)
	case ${amb_temp} in
		*"find the USB device"*)
			echo ""
			;;
		*)
			amb_temp=$(awk '{print $NF}' <<<$amb_temp |  sed 's/C//g')
			echo -n "scale=1;${amb_temp}/1" | grep -oE "-?[[:digit:]]+.[[:digit:]]"
	esac
} # ambienttemp

#function get_ip_addresses() {
#	# return up to 2 IPv4 address(es) comma separated
#	hostname -I | tr " " "
" | 
#		grep -E "^((25[0-5]|2[0-4][0-9]|[01]?[0-9][0-9]?).){3}(25[0-5]|2[0-4][0-9]|[01]?[0-9][0-9]?)$" | 
#		tail -n2 | sed ':a;N;$!ba;s/
/,/g'
#} # get_ip_addresses

function get_ip_addresses() {
	local ips=()
	for f in /sys/class/net/*; do
		local intf=$(basename $f)
		# match only interface names starting with e (Ethernet), br (bridge), w (wireless), r (some Ralink drivers use ra<number> format)
		if [[ $intf =~ $SHOW_IP_PATTERN ]]; then
			local tmp=$(ip -4 addr show dev $intf | awk '/inet/ {print $2}' | cut -d'/' -f1)
			# add both name and IP - can be informative but becomes ugly with long persistent/predictable device names
			#[[ -n $tmp ]] && ips+=("$intf: $tmp")
			# add IP only
			[[ -n $tmp ]] && ips+=("$tmp")
		fi
	done
	echo "${ips[@]}"
} # get_ip_addresses

function storage_info() {
	# storage info
	RootInfo=$(df -h /)
	root_usage=$(awk '/// {print $(NF-1)}' <<<${RootInfo} | sed 's/%//g')
	root_total=$(awk '/// {print $(NF-4)}' <<<${RootInfo})
	StorageInfo=$(df -h $STORAGE 2>/dev/null | grep $STORAGE)
	if [[ -n "${StorageInfo}" && ${RootInfo} != *$STORAGE* ]]; then
		storage_usage=$(awk '/// {print $(NF-1)}' <<<${StorageInfo} | sed 's/%//g')
		storage_total=$(awk '/// {print $(NF-4)}' <<<${StorageInfo})
	fi
} # storage_info

# query various systems and send some stuff to the background for overall faster execution.
# Works only with ambienttemp and batteryinfo since A20 is slow enough :)
amb_temp=$(ambienttemp &)
ip_address=$(get_ip_addresses &)
batteryinfo
storage_info
getboardtemp
critical_load=$(( 1 + $(grep -c processor /proc/cpuinfo) / 2 ))

# get uptime, logged in users and load in one take
UptimeString=$(uptime | tr -d ',')
time=$(awk -F" " '{print $3" "$4}' <<<"${UptimeString}")
load="$(awk -F"average: " '{print $2}'<<<"${UptimeString}")"
users="$(awk -F" user" '{print $1}'<<<"${UptimeString}")"
case ${time} in
	1:*) # 1-2 hours
		time=$(awk -F" " '{print $3" hour"}' <<<"${UptimeString}")
		;;
	*:*) # 2-24 hours
		time=$(awk -F" " '{print $3" hours"}' <<<"${UptimeString}")
		;;
esac

# memory and swap
mem_info=$(LC_ALL=C free -w 2>/dev/null | grep "^Mem" || LC_ALL=C free | grep "^Mem")
memory_usage=$(awk '{printf("%.0f",(($2-($4+$6+$7))/$2) * 100)}' <<<${mem_info})
memory_total=$(awk '{printf("%d",$2/1024)}' <<<${mem_info})
swap_info=$(LC_ALL=C free -m | grep "^Swap")
swap_usage=$( (awk '/Swap/ { printf("%3.0f", $3/$2*100) }' <<<${swap_info} 2>/dev/null || echo 0) | tr -c -d '[:digit:]')
swap_total=$(awk '{print $(2)}' <<<${swap_info})

# display info
display "System load" "${load%% *}" "${critical_load}" "0" "" "${load#* }"
printf "Up time:       x1B[92m%sx1B[0m		" "$time"
display "Local users" "${users##* }" "3" "2" ""
echo "" # fixed newline
display "Memory usage" "$memory_usage" "70" "0" " %" " of ${memory_total}MB"
display "Zram usage" "$swap_usage" "75" "0" " %" " of $swap_total""Mb"
printf "IP:            "
printf "x1B[92m%sx1B[0m" "$ip_address"
echo "" # fixed newline
a=0;b=0;c=0
display "CPU temp" "$board_temp" "45" "0" "°C" "" ; a=$?
display "Ambient temp" "$amb_temp" "40" "0" "°C" "" ; b=$?
(( ($a+$b) >0 )) && echo "" # new line only if some value is displayed
display "Usage of /" "$root_usage" "90" "1" "%" " of $root_total"
display "storage/" "$storage_usage" "90" "1" "%" " of $storage_total"
display "Battery" "$battery_percent" "20" "1" "%" "$status_battery_text"
echo ""
echo ""

效果

实际显示每种信息的首字段为绿色

System load:   0.89 0.94 0.89  	Up time:       8 days		
Memory usage:  67 % of 792MB  	IP:            10.0.1.3
CPU temp:      30°C           	
Usage of /:    14% of 6.7G