bash：输出/写入/附加一个带有时间戳和公共 IP 的 csv 文件

Question

I have an R script that gets the public IP by

system("curl ifconfig.me",intern = T )

and then writes/appends it in a CSV file

write.table(data.frame(start.script=start.time, runtime=round(Sys.time()-start.time,4), ip=myip), append = T, file = "/home/eic/ip.report.csv", row.names = F,sep = ",", col.names = !file.exists("/home/eic/ip.report.csv"))

the script runs with cron every minute.

However, i will be running it in an small raspberry Zero and the installation of R is almost 500MB

is it possible to do this with bash?

The output should create or append a CSV file with (time and public IP as strings). If the inte.net is not reachable, "Inte.net not reachable" should be output. It doesn't necessarily have to do curl ifconfig.me to check for inte.net connectivity. Checking for ping at 8.8.8.8 would be also an option. However it should output the public IP.

Thanks

Answer 1

#!/bin/bash
ip=$(curl --max-time 2 ifconfig.me 2>/dev/null) #Curl outputs some data on stderr. 2>/dev/null will remove that
hasInternet=$? #will be 0 if there was no error, make sure this line is directly after the curl line
curdate=$(date)
csvfile="file.csv" #right now this is a relative path to your working directory. For cron maybe better to use a absolute path

if [ $hasInternet -eq 0 ]; then
  echo "${curdate},${ip}" >> $csvfile #>> will add a new line to the file
else
  echo "${curdate},No internet" >> $csvfile
fi

I think this is a good start for your script. Might not be exactly as your original was, but I think you should be able to make the necessary changes.

Answer 2

msg=$(curl -s --max-time 3 icanhazip.com) ||
msg='Internet unreachable'

echo "$(date '+%Y-%m-%d %T %Z'),${msg:-Unkown}" >> /home/eic/ip.report.csv

Each line will look like:

2022-02-21 14:59:59,12.123.123.12 UTC

• Obviously, "Inte.net unreachable" means "icanhazip.com unreachable". Failing to ifconfig.me , and/or ping -c 1 -W 3 google.com to log connectivity, but not IP, may be worthwhile to reduce maintenance of an embedded device.
• I might even use a 5 second time out (instead of 3), for very slow connections, like bad satellite, proxies, etc.
• ${msg:-Unkown} replaces an empty response with Unkown .
• You can change the date format: man date .
• Add 2>/dev/null to curl if you don't want cron to log errors it may produce (eg if inte.net is down).
• More info on checking inte.net connectivity from the shell: https://unix.stackexchange.com/questions/190513/shell-scripting-proper-way-to-check-for-inte.net-connectivity