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do something else while waiting for an event, such as reboot

Terminal - do something else while waiting for an event, such as reboot
until (ssh root@10.1.1.39 2> /dev/null); do date; sleep 15; done
2011-03-08 08:42:12
User: greggster
Functions: sleep ssh
8
do something else while waiting for an event, such as reboot

until (ssh root@10.1.1.39 2> /dev/null); do date; sleep 15; done

In this case will execute "date" then "sleep 15" until we are able to ssh into server, such as after a reboot

Could also be like:

until ( ping 10.1.1.39 1> /dev/null); do echo "server 10.1.1.39 is down"; sleep 15; done

Alternatives

There are 2 alternatives - vote for the best!

Terminal - Alternatives

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What others think

Not that it makes any significant difference in this case, but those parentheses around the commands are not necessary. Also, that ping command will go on pinging forever unless you give it a count with the -c option, and as far as I'm aware, GNU ping only sets an error code if it also fails to transmit any packets. Which means, as long as ping's able to transmit its echo requests, 'echo "server 10.1.1.39 is down"; sleep 15' won't run even if ping doesn't receive any responses.

Comment by eightmillion 225 weeks and 2 days ago

yes the ping will need a -c arg - else it will as you say ping forever...

Comment by greggster 148 weeks ago

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