Package net-tools is not available, but is referred to by another package.

# ifconfig 설치
리눅스를 설치하고 ifconfig 를 실행하면 아래와 같이 에러 메시지가 출력된다.

실행 환경: Ubuntu 22.04

```
Command 'ifconfig' not found, but can be installed with:
sudo apt install net-tools
```
아, 그럼 net-tools 패키지를 설치하면 되겠거니 하고, 설치 명령어를 실행한다.
```
Reading package lists... Done
Building dependency tree... Done
Reading state information... Done
Package net-tools is not available, but is referred to by another package.
This may mean that the package is missing, has been obsoleted, or
is only available from another source

E: Package 'net-tools' has no installation candidate
```

해결 방법은 apt (Advanced Package Tool) 의 DB를 업데이트 하는 것이다.

( 아래 링크 참고 -> https://askubuntu.com/questions/14685/what-does-package-package-has-no-installation-candidate-mean)

```
$ sudo apt-get update
```

다시 net-tools 를 설치하면 잘 설치된다.