Bash script to ping 2 IP addresses, then -->

CruiserCZ · 04-03-2017, 03:53 AM

Hi,

I need help. Currently using OpenSUSE distribution and I need to create a bash script, that will ping two IP addreses and only do an action if both are unavailable. Is that possible somehow ?

Thank you very much,
any help is much appreciated

Turbocapitalist · 04-03-2017, 03:58 AM

Yes, see how to do conditional statements, as well as the full manual for ping

Code:

man ping

All programs produce an exit code and can thus be used in a conditional statement. If you want to save that exit code for later, then save the variable $? to another variable immediately after the program is run before doing anything else.

How far can you get with that? Which shell scripting guide or tutorial are you working from?

Habitual · 04-03-2017, 08:29 AM

Code:

for i in ip_one ip_two ; do ping -c 1 -w2 $i> /dev/null ; if [ $? -eq 0 ] ; then echo $i appears up; else echo $i ""may"" be down ; fi  ; done

Example:

Code:

for i in 185.156.173.235 52.202.3.120 ; do ping -c 1 -w2 $i> /dev/null ; if [ $? -eq 0 ] ; then echo $i is up; else echo $i ""may"" be down ; fi  ; done

provides

Code:

185.156.173.235 is up
52.202.3.120 may be down

Read the conditionals link provided by Turbocapatalist, it's used in my example.

That should do until "help" arrives.

jefro · 04-03-2017, 03:06 PM

Random thoughts.
I am less and less a fan of ping each year. Wonder if other means would provide better tests of connectivity?

Habitual · 04-03-2017, 05:46 PM

I don't trust it as "reliable" and it is firmly stuck in my noggin'.

Just sayin'
script unused since 2014-01-15

jefro · 04-04-2017, 03:31 PM

I was just thinking out loud. Didn't have a better way.

TB0ne · 04-04-2017, 04:54 PM

Quote:

Originally Posted by Habitual

I don't trust it as "reliable" and it is firmly stuck in my noggin'.

Just sayin'
script unused since 2014-01-15

When I don't trust ping, I use SNMP:

Code:

snmpget -v 1 -c public <some IP address/host> 1.3.6.1.2.1.1.1.0"

...and replace the version and community as needed too. That OID is the system OID, and that particular node will return the system description. 1.3.6.1.2.1.1.5 will return the system name as set in the SNMP configuration.

I trust that a *BIT* more, because I've seen systems respond to an ICMP ping, but be non-responsive otherwise. This, at least, indicates the system is functioning on SOME level past Layer 3.