How can i replace an empty line with a specific text using bash script? : <p>Hi I am having a text file . the file has some lines without text . I would like to replace these lines with some specific text .</p>

<p>log.txt </p>

<pre><code>{"id":0,"manufacturer":"cheverlot","model":"AC 3000ME 1002","description":"Culpa exercitation nulla amet excepteur amet sint voluptate elit consectetur. Sit eiusmod velit occaecat consequat pariatur mollit cupidatat ad velit ipsum reprehenderit ea labore aliquip. Nostrud ullamco minim nulla in ea nulla nisi Lorem laboris aute.\r\n","date":"3202-07-20T12:29:26 -01:00"}

{"id":1,"manufacturer":"Bugati","model":"AC 3000ME 1003","description":"Eiusmod magna laborum nulla labore esse. Qui velit nulla eiusmod excepteur anim veniam cupidatat proident incididunt proident non laborum irure aliqua. Magna exercitation eiusmod ad mollit pariatur commodo. Deserunt mollit Lorem do laboris pariatur reprehenderit consequat consectetur excepteur nostrud.\r\n","date":"11925-03-15T05:54:00 -00:00"}

{"id":2,"manufacturer":"Bugati","model":"AC 3000ME 1001","description":"Commodo cupidatat laborum aliquip mollit irure reprehenderit ipsum cillum officia labore Lorem aliqua reprehenderit. Lorem ad consectetur anim aute non tempor magna aliquip elit minim. Et laboris tempor velit non. Commodo amet laborum pariatur id et Lorem consectetur elit cupidatat aute eu proident quis nostrud. Do laboris ipsum officia pariatur deserunt ullamco qui. Eu tempor irure consectetur officia adipisicing cupidatat laboris non consectetur ad laboris commodo deserunt tempor.\r\n","date":"7679-11-22T08:16:34 -00:00"}

{"id":3,"manufacturer":"cheverlot","model":"AC 3000ME 1001","description":"Deserunt occaecat laboris laborum cupidatat nisi reprehenderit aute aute culpa. Sunt consequat fugiat dolor dolore dolor sint. Exercitation sunt adipisicing nostrud culpa non consequat anim est excepteur deserunt et excepteur. Minim eu cupidatat adipisicing quis occaecat deserunt magna ea.\r\n","date":"3959-09-20T09:24:42 -01:00"}

{"id":4,"manufacturer":"Audi","model":"AC 3000ME 1003","description":"Magna commodo fugiat ea consequat incididunt. Adipisicing commodo duis consequat officia esse et ea excepteur exercitation anim laboris dolor ad. Officia magna incididunt irure sit et minim adipisicing aliquip officia magna Lorem qui veniam quis. Lorem elit et deserunt exercitation nisi sit non aliqua officia veniam consequat. Non ut fugiat nisi nulla exercitation nostrud. Ut culpa reprehenderit mollit commodo officia irure labore fugiat cillum tempor esse aliqua est ipsum.\r\n","date":"8024-05-26T04:22:34 -01:00"}
</code></pre>

<p>Expected result</p>

<pre><code>{"index":{}}
{"id":0,"manufacturer":"cheverlot","model":"AC 3000ME 1002","description":"Culpa exercitation nulla amet excepteur amet sint voluptate elit consectetur. Sit eiusmod velit occaecat consequat pariatur mollit cupidatat ad velit ipsum reprehenderit ea labore aliquip. Nostrud ullamco minim nulla in ea nulla nisi Lorem laboris aute.\r\n","date":"3202-07-20T12:29:26 -01:00"}
{"index":{}}
{"id":1,"manufacturer":"Bugati","model":"AC 3000ME 1003","description":"Eiusmod magna laborum nulla labore esse. Qui velit nulla eiusmod excepteur anim veniam cupidatat proident incididunt proident non laborum irure aliqua. Magna exercitation eiusmod ad mollit pariatur commodo. Deserunt mollit Lorem do laboris pariatur reprehenderit consequat consectetur excepteur nostrud.\r\n","date":"11925-03-15T05:54:00 -00:00"}
{"index":{}}
{"id":2,"manufacturer":"Bugati","model":"AC 3000ME 1001","description":"Commodo cupidatat laborum aliquip mollit irure reprehenderit ipsum cillum officia labore Lorem aliqua reprehenderit. Lorem ad consectetur anim aute non tempor magna aliquip elit minim. Et laboris tempor velit non. Commodo amet laborum pariatur id et Lorem consectetur elit cupidatat aute eu proident quis nostrud. Do laboris ipsum officia pariatur deserunt ullamco qui. Eu tempor irure consectetur officia adipisicing cupidatat laboris non consectetur ad laboris commodo deserunt tempor.\r\n","date":"7679-11-22T08:16:34 -00:00"}
{"index":{}}
{"id":3,"manufacturer":"cheverlot","model":"AC 3000ME 1001","description":"Deserunt occaecat laboris laborum cupidatat nisi reprehenderit aute aute culpa. Sunt consequat fugiat dolor dolore dolor sint. Exercitation sunt adipisicing nostrud culpa non consequat anim est excepteur deserunt et excepteur. Minim eu cupidatat adipisicing quis occaecat deserunt magna ea.\r\n","date":"3959-09-20T09:24:42 -01:00"}
{"index":{}}
{"id":4,"manufacturer":"Audi","model":"AC 3000ME 1003","description":"Magna commodo fugiat ea consequat incididunt. Adipisicing commodo duis consequat officia esse et ea excepteur exercitation anim laboris dolor ad. Officia magna incididunt irure sit et minim adipisicing aliquip officia magna Lorem qui veniam quis. Lorem elit et deserunt exercitation nisi sit non aliqua officia veniam consequat. Non ut fugiat nisi nulla exercitation nostrud. Ut culpa reprehenderit mollit commodo officia irure labore fugiat cillum tempor esse aliqua est ipsum.\r\n","date":"8024-05-26T04:22:34 -01:00"}
</code></pre>

<p>so in short i want to replace those blank lines with this text {"index":{}}</p>

<p>any idea how can i do it in shell script .
thank you </p>
