UNIX for Dummies Questions & Answers

Hi,

I am trying to get a result out of this but fails please help. Have two files /tmp/1 & /tmp/hosts. 


/tmp/1
IP=123.456.789.01
WAS_HOSTNAME=abcdefgh.was.tb.dsdc

/tmp/hosts
123.456.789.01

I want this result in /tmp/hosts if hostname is already there dont want duplicate entry.

This is wrong
123.456.789.01 abcdefgh.was.tb.dsdc abcdefgh.was.tb.dsdc

This is correct
123.456.789.01 abcdefgh.was.tb.dsdc

Trying with this:

if grep abcdefgh.was.tb.dsdc /tmp/hosts; then
. /tmp/1 && sed -i "s/^$IP\(.*\)$/$IP\1 $WAS_HOSTNAME/" /tmp/hosts;
fi

Thanks in advance

awk -F= 'NR==FNR{I[$1];next}$2 in I{v=$2;getline;print v,$2}' /tmp/hosts /tmp/1

awk ... > /tmp/$$; mv /tmp/$$ /tmp/hosts

Hi Yoda,

I tried that, when for first time i run this it writes and moves the content required. But, when i run it second time it creates empty redirect file, as nothing is there to write and the same is moved to original file. So, getting an empty file on second attempt.

cp -p /tmp/hosts /tmp/hosts.org; awk -F= 'NR==FNR{I[$1];next}$2 in I{v=$2;getline;print v,$2}' /tmp/hosts /tmp/1 > /tmp/$$; mv /tmp/$$ /tmp/hosts

Please suggest.

Thanks