CODEWITHSUNDEEP
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Eyüp Alemdar
Eyüp Alemdar

Reputation: 233

Linux Script: if [ "$hostname" != "(none)" ] comparison doesn't work

I'm getting hostname and ip address from server(ubuntu 12.04) as explained here. It works correctly. After a while, i realize that server returns "(none)" as hostname when it is offline. Now i'm trying to eliminate this error by comparing hostname with "(none)". I tried all of these(*) but none of them works:

-- Getting hostname here    
hostname=$(grep "host-name" /var/lib/dhcp/dhclient.${interface}.leases | tail -n1 | cut -d"\"" -f2 | cut -d"." -f1)

-- Trying to compare it with "(none)"
    * if [ "$hostname" != "(none)" ] then ... else ... fi
    * if [[ $hostname != "(none)" ]] then ... else ... fi
    * nouser="(none)"  if [ "$hostname" != "$nouser" ] then ... else ... fi

What am i doing wrong ? Thx for any help.

Upvotes: 2

Views: 2842

Answers (3)

Wilf
Wilf

Reputation: 743

Use $HOSTNAME - my reasoning, which can user to validate other $ variables:

wilf@comp:~$ echo $hostname

wilf@comp:~$ echo $HOSTNAME
comp
wilf@comp:~$

For some reason, $hostname does not seem to work (Ubuntu 13.10, haven't tried this on other Linuxes)

Upvotes: 0

armandino
armandino

Reputation: 18548

This should work;

hostname="(foo)"
if [ "$hostname" == "(foo)" ]; then echo "equals"; else echo "not equals"; fi

Upvotes: 1

SzG
SzG

Reputation: 12619

You need a semicolon after ]

if [ ... ]; then ...; else ...; fi

or newlines:

if [ ... ]
then
   ...
else
   ...
fi

Upvotes: 1

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