How to persist resolv.conf modifications

Default resolv.conf in my Ubuntu box is as follows,

udara@udara-home:~$ cat /etc/resolv.conf
# Dynamic resolv.conf(5) file for glibc resolver(3) generated by resolvconf(8)
#     DO NOT EDIT THIS FILE BY HAND -- YOUR CHANGES WILL BE OVERWRITTEN
nameserver 127.0.1.1

Assume a scenario where I need to use a different DNS.. Eg: -google dns- 8.8.8.8

I can achieve this by modifying above resolv.conf, but that change won't persists after Ubuntu box restart, networking restart or my router restart.

How to persist my change,

Open /etc/network/interfaces using your favorite text editor, in my case it's vi :)

sudo vi /etc/network/interfaces

Update /etc/network/interfaces according to your preference. You can append dns-nameservers 8.8.8.8 to the end.


Eg:-

# interfaces(5) file used by ifup(8) and ifdown(8)
auto lo
iface lo inet loopback
dns-nameservers 8.8.8.8

Note:- I tried different alternatives like update resolv.conf using a bash script during server restart, adding immutable characteristic to resolv.conf using chattr tool. But above is the only viable solution I can recommend to someone.

Git merge to restore lost commit

Lets start from a status like following,

udara@udara-home:~/workspace/USSD-Reminder$ git status
# On branch new-feature
# Your branch is ahead of 'origin/new-feature' by 1 commit.
#   (use "git push" to publish your local commits)
#
nothing to commit, working directory clean

So here my local branch is one commit ahead from the remote. Assume mistakenly I did a git reset --hard HEAD^. This will remove my last commit and now I need to find a way to undo my last command.

When we issue the git reset command, commit goes to dangling state and commit is not going to remove permanently. luckily !!

IMPORTANT:

Make sure you don't run git gc until you restore the lost commit. git gc command will trigger the garbage collector and remove all commits which are in dangling state.


Let's start the restoring process....

1. We need to find the SHA1 of the deleted commit so we can bring it back.

 git fsck --lost-found

git fsck command will list down all commits which are in dangling state.

udara@udara-home:~/workspace/USSD-Reminder$ git fsck --lost-found
Checking object directories: 100% (256/256), done.
Checking objects: 100% (16/16), done.
dangling commit 5e3079cc8ac9e15cbfc1f513d249678c0893feab

So we have the SHA1 of the commit which needs to restore.

2. Lets merge this commit.

git merge <SHA1>

udara@udara-home:~/workspace/USSD-Reminder$ git merge 5e3079cc8ac9e15cbfc1f513d249678c0893feab
Updating 0ffdab3..5e3079c
Fast-forward
 config.php | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

Now if we run the git status command it should mention that my local branch is one commit ahead than the remote.