Ssh – How to check that a remote computer is online for ssh / script access

backupnetworkingpingscriptingssh

I'm writing a script that will backup data from my laptop to an Ubuntu server.
To do so, I'm looking for a (ba)sh command to test if the server is available before starting the backup. something like ping on port 22 that returns a boolean.

How can I do this?

Best Answer

Like this:

nc -z hostname 22 > /dev/null
echo $?

If it's 0 then it's available. If it's 1 then it's not.

Related Solutions

How to you get ping to print human readable timestamps

From : https://stackoverflow.com/questions/14036116/convert-timestamp-to-datetime-with-sed

with bit of scripting...

ping -D localhost | while read row 
do 
  awk '{ sub(/[0-9]{10}/, strftime("%Y-%m-%d %H:%M:%S", substr($0,2,10))) }1' <<< "$row"
done

Runs as

$ ping -D localhost | while read row; do awk '{ sub(/[0-9]{10}/, strftime("%Y-%m-%d %H:%M:%S", substr($0,2,10))) }1' <<< "$row" ; done
PING localhost (127.0.0.1) 56(84) bytes of data.
[2014-11-10 16:06:40.145811] 64 bytes from localhost (127.0.0.1): icmp_req=1 ttl=64 time=0.045 ms
[2014-11-10 16:06:41.144926] 64 bytes from localhost (127.0.0.1): icmp_req=2 ttl=64 time=0.040 ms

Best Answer

Related Solutions

How to you get ping to print human readable timestamps

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