Can't launch mongodb - mongodb

Question

I don't know where I went wrong,
but there is an error after error going on here, first it was
STORAGE [initandlisten] exception in initAndListen: 20 Attempted to create a lock file on a read-only directory: /var/lib/mongodb, terminating
I fixed with addition of permissions with this command:
sudo chmod -R go+w /var/lib/mongodb
, then
couldn't open /var/lib/mongodb/local.0 Operation not permitted
fixed it with another sort of permissions(
sudo chown -R $USER /var/lib/mongodb
)
now its complaining about:
F JOURNAL [initandlisten] dbexception during recovery: 13544 recover error couldn't open /var/lib/mongodb/journal/j._0
2017-11-20T13:19:16.443+0200 I STORAGE [initandlisten] exception in initAndListen: 13544 recover error couldn't open /var/lib/mongodb/journal/j._0, terminating
Update:
Fixed that as well with
sudo chown -R mongodb:mongodb /var/lib/mongodb
now its
exception in initAndListen: 13440 bad offset:0 accessing file: /var/lib/mongodb/local.0. See http://dochub.mongodb.org/core/data-recovery, terminating
what is happening? I mean my Ubuntu is not some super secured version,
I wish there was some
mongod --repair
command for me to use, but there isn't, whenever I try to do it it complains about
exception in initAndListen: 29 Data directory /data/db not found., terminating
although in the etc/mongod.config the specified path is /var/lib/mongodb (that's where I was giving all this permissions at)
Edit:
fixed that with the CMD "do sudo mkdir /data", the repair run its course successfully, but it didn't help me.
so what do I do? how to fix it?
how to run the Mongodb?
additional info: I ran it using
sudo service mongod start