我想通过curl安装节点。但不幸的是，由于此qmail错误，我无法成功。稍后我想使用pip安装Tkinter，但由于此相同错误而无法执行此操作。这是什么以及如何解决？
在终端机上使用此功能时：sudo vi /etc/hosts
这出现了
127.0.0.1 localhost
127.0.1.1 shahin-UX360UAK
# The following lines are desirable for IPv6 capable hosts
::1 ip6-localhost ip6-loopback
fe00::0 ip6-localnet
ff00::0 ip6-mcastprefix
ff02::1 ip6-allnodes
ff02::2 ip6-allrouters
并尝试安装curl之后：sudo apt install curl
出现此错误：
Reading package lists... Done
Building dependency tree
Reading state information... Done
curl is already the newest version (7.58.0-2ubuntu3.5).
0 upgraded, 0 newly installed, 0 to remove and 40 not upgraded.
2 not fully installed or removed.
After this operation, 0 B of additional disk space will be used.
Do you want to continue? [Y/n] y
Setting up qmail (1.06-6) ...
The hostname -f command returned: $1
Your system needs to have a fully qualified domain name (fqdn) in
order to install the var-qmail packages.
Installation aborted.
dpkg: error processing package qmail (--configure):
installed qmail package post-installation script subprocess returned error exit status 1
dpkg: dependency problems prevent configuration of qmail-run:
qmail-run depends on qmail (>= 1.06-2.1); however:
Package qmail is not configured yet.
dpkg: error processing package qmail-run (--configure):
dependency problems - leaving unconfigured
No apport report written because the error message indicates its a followup error from a previous failure.
Errors were encountered while processing:
qmail
qmail-run
E: Sub-process /usr/bin/dpkg returned an error code (1)
由于同样的错误，我什至无法安装qmail。