Score:1

Ubuntu

Check a host file for modification and if missing add it

Mark Vetter

3/15/24, 4:47 PM

I'm using docker in which the container has its own /etc/hosts file. It gets cleared out when rebooting. I'd like to create a script to check for an entry and if missing add it.

So if /etc/hosts has an entry that says:

10.1.1.1 important-server

Then do nothing. If not do:

echo "10.1.1.1 important-server" >> /etc/hosts

I'm assuming I can use sed or awk or something like that for the pattern matching.

1 + 5

scripts

hosts

sed

awk

Rinzwind

3/15/24, 4:53 PM

You should add `--add-host="import-server:10.1.1.1"` to the docker run command OR docker-compose.yml file if you use docker-compose.

Raffa

3/15/24, 5:06 PM

`grep` with the option `-q` will `exit 0`(*success*) at first match and will `exit > 0` otherwise ... So, ... `/bin/grep -Fq '10.1.1.1 important-server' /etc/hosts || echo "10.1.1.1 important-server" >> /etc/hosts`

Gilles Quenot

3/15/24, 5:45 PM

Already gave a response of this earlier ;) And the spaces are not fixed like this in **RealLife©®™**

Mark Vetter

3/16/24, 5:12 PM

--add-host "import-server:10.1.1.1" works. It should not have the =

Gilles Quenot

3/16/24, 6:19 PM

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Score:1

Ubuntu

Gilles Quenot

3/15/24, 5:04 PM

As said by Rinzwind in comments:

You should add --add-host="import-server:10.1.1.1" to the docker run command OR docker-compose.yml file if you use docker-compose.

Or in shell:

sudo -s
grep -Pq '^10\.1\.1\.1\s+important-server' /etc/hosts ||
    echo '10.1.1.1 important-server' >> /etc/hosts
exit

+ 1

Mark Vetter

4/2/24, 1:52 AM

Correct except change = to :

Elon Musk

I sit in a Tesla and translated this thread with Ai:

EN: Check a host file for modification and if missing add it

Post an answer

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