How to restore Line messages from Titanium Backup?

It seems that Line *(a messaging app like WhatsApp)* is one that I cannot easily restore app data (messages) through Titanium Backup. There is a [whole thread on XDA](http://forum.xda-developers.com/showthread.php?t=2487955) , highlighting [one post](https://forum.xda-developers.com/t/guide-how-to-restore-import-line-chat-history.2487955/post-47583553) : > [...] > > 1. Restore Line with Titanium Backup (app+data) (DON'T OPEN THE LINE APP YET!) > > 2. Log into a root shell and delete the previous settings: > >

>    sqlite3 /data/data/jp.naver.line.android/databases/naver_line
>    delete from setting;
>    .quit
>

> 3. [...] It looks quite difficult and I am not even sure it's correct. Can anyone confirm before I try? Also, what is a root shell? Is that some form of an app?