How can I verify if time is set correctly on server in my bash script?

Question

I'm working on ultimate backup script for very important server. My script already:

• creates a backup
• verifies copied file(-s)
• verifies gz archive
• compares MD5 on local and remote after sending file to remote server via scp
• removes monthly backups older than 365, weekly backups older than 31 days, daily backups older than 7 days, hourly backups older than 24 hours
• checks for available disk space on local and remote machine
• sends email report if some errors ocurred
• sends email report for weekly backups

In addition to all this, I miss one important thing - clock verification on local and remote because it affects the naming and removal of copies.

How can I make sure if date and time are set correctly in bash in a simple and reliable way?

If possible - it would be nice if that method could work on Windows server with cygwin.

I'm not asking for complete solution, just advice for taking correct and not complex approach.

Answer 1

You can use command in Linux:

date +%s

and in Windows (PowerShell)

Get-Date -UFormat %s

to get epoch time. Those numbers can be easy compared.

P.S. For Windows you may need to strip the number to integer like this:

$t3 = (Get-Date -UFormat %s).split(',')[0]
echo $t3

N.B. Here comma , is my decimal number delimiter. Depend of your language you may need to change it.

This command will give you Epoch time from external source (to compare with your machines)

curl -s "http://worldtimeapi.org/api/timezone/Europe/Rome" |jq '.unixtime'

Feel free to change your timezone