Sun Bear's questions

为了通过 Line Out 内置音频和蓝牙扬声器播放音乐，我实现了@DidierL的答案，创建了一个新的“同时输出”作为输出设备。

然后我注意到蓝牙说话声音略有延迟。为了解决这个延迟问题，我尝试了@PoDuck的答案。即实施

#!/bin/bash

BLUEZCARD=$(pactl list cards short | egrep -o bluez.*[[:space:]])
pactl set-card-profile $BLUEZCARD a2dp_sink
pactl set-card-profile $BLUEZCARD headset_head_unit
pactl set-card-profile $BLUEZCARD a2dp_sink

由于此解决方案无法纠正延迟，我尝试了：

#!/bin/bash

BLUEZCARD=$(pactl list cards short | egrep -o bluez.*[[:space:]])
pactl set-card-profile $BLUEZCARD off
pactl set-card-profile $BLUEZCARD a2dp_sink
pactl set-card-profile $BLUEZCARD off
pactl set-card-profile $BLUEZCARD a2dp_sink

不幸的是，这个设置破坏了“同步输出”设备的性能。它不会播放任何声音。

此外，如果明确选择，则只有 Line Out 内置音频才有效。当明确选择蓝牙扬声器时，声音非常静音。

我不知道如何撤消 Ubuntu 24.04 中的混乱，正如@PoDuck 的回答中提到的，没有撤消自定义快捷方式的选项。

然后单击右侧的“已禁用”以设置键盘快捷键来执行脚本。

我该如何收拾残局？

更新：

我刚刚发现qpwgraph。下面给出了一个视觉效果。我注意到几个重复的模块，我不知道它是怎么出现的。

任何关于该做什么的建议都是很好的。

当unbound使用配置时--enable-dnstap，无法定位protobuf-c。

$ ./configure --enable-dnstap
...
...
...
checking for protoc-c... no
configure: error: The protoc-c program was not found. Please install protobuf-c!

不过，protobuf-c看上去已经安装好了。

$ sudo apt search protobuf-c
Sorting... Done
Full Text Search... Done
libprotobuf-c-dev/stable,now 1.4.1-1+b1 armhf [installed]
  Protocol Buffers C static library and headers (protobuf-c)

libprotobuf-c1/stable,now 1.4.1-1+b1 armhf [installed,automatic]
  Protocol Buffers C shared library (protobuf-c)

librust-prometheus+protobuf-codegen-pure-dev/stable 0.13.3-1 armhf
  Prometheus instrumentation library for Rust applications - feature "protobuf-codegen-pure" and 1 more

librust-protobuf-codegen-dev/stable 2.27.1-1+b2 armhf
  Code generator for rust-protobuf - Rust source code

librust-protobuf-codegen-pure-dev/stable 2.27.1-1 armhf
  Pure-rust codegen for protobuf using protobuf-parser crate - Rust source code

protobuf-c-compiler/stable 1.4.1-1+b1 armhf
  Protocol Buffers C compiler (protobuf-c)

protobuf-codegen/stable 2.27.1-1+b2 armhf
  Code generator for rust-protobuf

protobuf-compiler/stable 3.21.12-3 armhf
  compiler for protocol buffer definition files

protobuf-compiler-grpc/stable 1.51.1-3+b1 armhf
  high performance general RPC framework - protobuf plugin

protobuf-compiler-grpc-java-plugin/stable 1.41.3+ds-1 armhf
  high performance general RPC framework - protobuf Java plugin  
$ dpkg -l | grep protobuf
ii  libprotobuf-c-dev:armhf              1.4.1-1+b1                              armhf        Protocol Buffers C static library and headers (protobuf-c)
ii  libprotobuf-c1:armhf                 1.4.1-1+b1                              armhf        Protocol Buffers C shared library (protobuf-c)
$ sudo find / -name libprotobuf-c1
/usr/share/doc/libprotobuf-c1
$ sudo find / -name libprotobuf-c-dev
/usr/share/doc/libprotobuf-c-dev
$ ls /usr/bin/ | grep proto
$ ls /usr/local/bin/ | grep proto
$ ls /bin/ | grep proto
$ ls /usr/lib/ | grep proto
$ ls /usr/local/lib/ | grep proto
$ ls /lib/ | grep proto
$

尽管已经安装了 protobuf-c 库或程序，但我找不到它。

我该如何解决这个配置问题？

更新：

我从这个答案中发现库名是libprotobuf-c.so.1。

其位置是通过以下方式找到的：

$ sudo find / -name libprotobuf-c.so.1
/usr/lib/arm-linux-gnueabihf/libprotobuf-c.so.1
$

我尝试通过以下方式将此文件链接到/usr/local/lib（未绑定的默认安装库目录）

$ ln -s /usr/lib/arm-linux-gnueabihf/libprotobuf-c.so.1 

并重新运行

$ ./configure --enable-dnstap

并且仍然收到与上述相同的错误消息。

我进一步尝试：

./configure --enable-dnstap --with-protobuf-c=/usr/lib/arm-linux-gnueabihf/libprotobuf-c.so.1

并且仍然收到与上述相同的错误消息。

我尝试配置的非绑定版本是 1.22.0。

此问题不重复How do I find the package that provided a file?。原因：

1. 我已经在使用dpkg。
2. 我发现使用apt search更合适，因为它显示了与描述相关的所有其他包protobuf-c。
3. 除了 之外libprotobuf-c，unbound还使用protoc-c​​程序（由未绑定成员告知我），安装后即可使用protobuf-c-compiler（参见@steeldriver 评论）。使用 不会泄露此信息dpkg。

我已将 Unbound 配置为：

1. 在 LAN 的所有接口上监听域查询，
2. 通过 TLS 将这些域查询转发到外部 DNS 解析器，
3. 从外部DNS解析器接收解析后的域名IP并返回给相应的客户端。

如何验证此类配置是否有效？特别是，如何验证：

1. Unbound 是否已通过 TLS 将域查询转发到所需的外部 DNS 解析器？
2. 解析的域名 IPS 来自外部 DNS 解析器，并且不由 Unbound 解析？

dig以下是来自ging的两个结果google.com。我如何使用这些结果进行上述验证？

root@DNS:/etc/unbound# dig google.com A @192.168.1.50 -p 3000

; <<>> DiG 9.18.28-0ubuntu0.24.04.1-Ubuntu <<>> google.com A @192.168.1.50 -p 3000
;; global options: +cmd
;; Got answer:
;; ->>HEADER<<- opcode: QUERY, status: NOERROR, id: 22452
;; flags: qr rd ra; QUERY: 1, ANSWER: 6, AUTHORITY: 0, ADDITIONAL: 1

;; OPT PSEUDOSECTION:
; EDNS: version: 0, flags:; udp: 1232
;; QUESTION SECTION:
;google.com.            IN  A

;; ANSWER SECTION:
google.com.     300 IN  A   142.251.175.138
google.com.     300 IN  A   142.251.175.100
google.com.     300 IN  A   142.251.175.113
google.com.     300 IN  A   142.251.175.101
google.com.     300 IN  A   142.251.175.139
google.com.     300 IN  A   142.251.175.102

;; Query time: 12 msec
;; SERVER: 192.168.1.50#3000(192.168.1.50) (UDP)
;; WHEN: Wed Oct 30 14:04:16 UTC 2024
;; MSG SIZE  rcvd: 135

root@DNS:/etc/unbound# dig google.com A @192.168.1.50 -p 3000

; <<>> DiG 9.18.28-0ubuntu0.24.04.1-Ubuntu <<>> google.com A @192.168.1.50 -p 3000
;; global options: +cmd
;; Got answer:
;; ->>HEADER<<- opcode: QUERY, status: NOERROR, id: 39764
;; flags: qr rd ra; QUERY: 1, ANSWER: 6, AUTHORITY: 0, ADDITIONAL: 1

;; OPT PSEUDOSECTION:
; EDNS: version: 0, flags:; udp: 1232
;; QUESTION SECTION:
;google.com.            IN  A

;; ANSWER SECTION:
google.com.     300 IN  A   142.251.175.139
google.com.     300 IN  A   142.251.175.113
google.com.     300 IN  A   142.251.175.100
google.com.     300 IN  A   142.251.175.101
google.com.     300 IN  A   142.251.175.138
google.com.     300 IN  A   142.251.175.102

;; Query time: 184 msec
;; SERVER: 192.168.1.50#3000(192.168.1.50) (UDP)
;; WHEN: Wed Oct 30 14:05:30 UTC 2024
;; MSG SIZE  rcvd: 135

以下是重新启动并运行上述 dig 命令两次后的unbound.log日志。我可以看到提到了外部 DNS 解析器，但我不明白哪一行显示它已解析域并将结果返回给 unbound。verbosity: 3unbound.service

[1730296502] unbound[6506:0] info: service stopped (unbound 1.19.2).
[1730296502] unbound[6506:0] info: server stats for thread 0: 0 queries, 0 answers from cache, 0 recursions, 0 prefetch, 0 rejected by ip ratelimiting
[1730296502] unbound[6506:0] info: server stats for thread 0: requestlist max 0 avg 0 exceeded 0 jostled 0
[1730296502] unbound[6506:0] info: server stats for thread 1: 0 queries, 0 answers from cache, 0 recursions, 0 prefetch, 0 rejected by ip ratelimiting
[1730296502] unbound[6506:0] info: server stats for thread 1: requestlist max 0 avg 0 exceeded 0 jostled 0
[1730296502] unbound[6506:0] info: server stats for thread 2: 0 queries, 0 answers from cache, 0 recursions, 0 prefetch, 0 rejected by ip ratelimiting
[1730296502] unbound[6506:0] info: server stats for thread 2: requestlist max 0 avg 0 exceeded 0 jostled 0
[1730296502] unbound[6506:0] info: server stats for thread 3: 0 queries, 0 answers from cache, 0 recursions, 0 prefetch, 0 rejected by ip ratelimiting
[1730296502] unbound[6506:0] info: server stats for thread 3: requestlist max 0 avg 0 exceeded 0 jostled 0
[1730296503] unbound[6658:0] debug: module config: "subnetcache validator iterator"
[1730296503] unbound[6658:0] notice: init module 0: subnetcache
[1730296503] unbound[6658:0] warning: subnetcache: serve-expired is set but not working for data originating from the subnet module cache.
[1730296503] unbound[6658:0] warning: subnetcache: prefetch is set but not working for data originating from the subnet module cache.
[1730296503] unbound[6658:0] debug: subnetcache: option registered (8)
[1730296503] unbound[6658:0] notice: init module 1: validator
[1730296503] unbound[6658:0] notice: init module 2: iterator
[1730296503] unbound[6658:0] debug: target fetch policy for level 0 is 3
[1730296503] unbound[6658:0] debug: target fetch policy for level 1 is 2
[1730296503] unbound[6658:0] debug: target fetch policy for level 2 is 1
[1730296503] unbound[6658:0] debug: target fetch policy for level 3 is 0
[1730296503] unbound[6658:0] debug: target fetch policy for level 4 is 0
[1730296503] unbound[6658:0] debug: Forward zone server list:
[1730296503] unbound[6658:0] info: DelegationPoint<dns.quad9.net.>: 0 names (0 missing), 4 addrs (0 result, 4 avail) parentNS
[1730296503] unbound[6658:2] debug: Forward zone server list:
[1730296503] unbound[6658:2] info: DelegationPoint<dns.quad9.net.>: 0 names (0 missing), 4 addrs (0 result, 4 avail) parentNS
[1730296503] unbound[6658:0] debug: cache memory msg=66104 rrset=66104 infra=7952 val=66400 subnet=74536
[1730296503] unbound[6658:1] debug: Forward zone server list:
[1730296503] unbound[6658:1] info: DelegationPoint<dns.quad9.net.>: 0 names (0 missing), 4 addrs (0 result, 4 avail) parentNS
[1730296503] unbound[6658:0] info: start of service (unbound 1.19.2).
[1730296503] unbound[6658:2] debug: cache memory msg=66104 rrset=66104 infra=7952 val=66400 subnet=74536
[1730296503] unbound[6658:3] debug: Forward zone server list:
[1730296503] unbound[6658:3] info: DelegationPoint<dns.quad9.net.>: 0 names (0 missing), 4 addrs (0 result, 4 avail) parentNS
[1730296503] unbound[6658:1] debug: cache memory msg=66104 rrset=66104 infra=7952 val=66400 subnet=74536
[1730296503] unbound[6658:3] debug: cache memory msg=66104 rrset=66104 infra=7952 val=66400 subnet=74536
[1730297056] unbound[5388:0] debug: subnetcache[module 0] operate: extstate:module_state_initial event:module_event_new
[1730297056] unbound[5388:0] info: subnetcache operate: query google.com. A IN
[1730297056] unbound[5388:0] debug: validator[module 1] operate: extstate:module_state_initial event:module_event_pass
[1730297056] unbound[5388:0] info: validator operate: query google.com. A IN
[1730297056] unbound[5388:0] debug: iterator[module 2] operate: extstate:module_state_initial event:module_event_pass
[1730297056] unbound[5388:0] info: resolving google.com. A IN
[1730297056] unbound[5388:0] info: resolving (init part 2):  google.com. A IN
[1730297056] unbound[5388:0] info: resolving (init part 3):  google.com. A IN
[1730297056] unbound[5388:0] info: processQueryTargets: google.com. A IN
[1730297056] unbound[5388:0] info: sending query: google.com. A IN
[1730297056] unbound[5388:0] debug: sending to target: <google.com.> 216.239.38.10#53
[1730297056] unbound[5388:0] debug: cache memory msg=70045 rrset=100203 infra=29147 val=67208 subnet=74536
[1730297056] unbound[5388:0] debug: iterator[module 2] operate: extstate:module_wait_reply event:module_event_reply
[1730297056] unbound[5388:0] info: iterator operate: query google.com. A IN
[1730297056] unbound[5388:0] info: response for google.com. A IN
[1730297056] unbound[5388:0] info: reply from <google.com.> 216.239.38.10#53
[1730297056] unbound[5388:0] info: query response was ANSWER
[1730297056] unbound[5388:0] info: finishing processing for google.com. A IN
[1730297056] unbound[5388:0] debug: validator[module 1] operate: extstate:module_wait_module event:module_event_moddone
[1730297056] unbound[5388:0] info: validator operate: query google.com. A IN
[1730297056] unbound[5388:0] debug: subnetcache[module 0] operate: extstate:module_wait_module event:module_event_moddone
[1730297056] unbound[5388:0] info: subnetcache operate: query google.com. A IN
[1730297056] unbound[5388:0] debug: cache memory msg=70045 rrset=100203 infra=29147 val=67208 subnet=74536
[1730297130] unbound[5379:0] debug: subnetcache[module 0] operate: extstate:module_state_initial event:module_event_new
[1730297130] unbound[5379:0] info: subnetcache operate: query google.com. A IN
[1730297130] unbound[5379:0] debug: validator[module 1] operate: extstate:module_state_initial event:module_event_pass
[1730297130] unbound[5379:0] info: validator operate: query google.com. A IN
[1730297130] unbound[5379:0] debug: iterator[module 2] operate: extstate:module_state_initial event:module_event_pass
[1730297130] unbound[5379:0] info: resolving google.com. A IN
[1730297130] unbound[5379:0] info: resolving (init part 2):  google.com. A IN
[1730297130] unbound[5379:0] info: resolving (init part 3):  google.com. A IN
[1730297130] unbound[5379:0] info: processQueryTargets: google.com. A IN
[1730297130] unbound[5379:0] info: sending query: google.com. A IN
[1730297130] unbound[5379:0] debug: sending to target: <com.> 2001:503:83eb::30#53
[1730297130] unbound[5379:0] debug: cache memory msg=78073 rrset=130165 infra=41184 val=69264 subnet=74536
[1730297130] unbound[5379:0] debug: iterator[module 2] operate: extstate:module_wait_reply event:module_event_noreply
[1730297130] unbound[5379:0] info: iterator operate: query google.com. A IN
[1730297130] unbound[5379:0] info: processQueryTargets: google.com. A IN
[1730297130] unbound[5379:0] info: sending query: google.com. A IN
[1730297130] unbound[5379:0] debug: sending to target: <com.> 192.41.162.30#53
[1730297130] unbound[5379:0] debug: cache memory msg=78073 rrset=130165 infra=41184 val=69264 subnet=74536
[1730297130] unbound[5379:0] debug: iterator[module 2] operate: extstate:module_wait_reply event:module_event_reply
[1730297130] unbound[5379:0] info: iterator operate: query google.com. A IN
[1730297130] unbound[5379:0] info: response for google.com. A IN
[1730297130] unbound[5379:0] info: reply from <com.> 192.41.162.30#53
[1730297130] unbound[5379:0] info: query response was REFERRAL
[1730297130] unbound[5379:0] info: processQueryTargets: google.com. A IN
[1730297130] unbound[5379:0] info: sending query: google.com. A IN
[1730297130] unbound[5379:0] debug: sending to target: <google.com.> 216.239.32.10#53
[1730297130] unbound[5379:0] debug: cache memory msg=78073 rrset=132972 infra=41184 val=69414 subnet=74536
[1730297130] unbound[5379:0] debug: iterator[module 2] operate: extstate:module_wait_reply event:module_event_reply
[1730297130] unbound[5379:0] info: iterator operate: query google.com. A IN
[1730297130] unbound[5379:0] info: response for google.com. A IN
[1730297130] unbound[5379:0] info: reply from <google.com.> 216.239.32.10#53
[1730297130] unbound[5379:0] info: query response was ANSWER
[1730297130] unbound[5379:0] info: finishing processing for google.com. A IN
[1730297130] unbound[5379:0] debug: validator[module 1] operate: extstate:module_wait_module event:module_event_moddone
[1730297130] unbound[5379:0] info: validator operate: query google.com. A IN
[1730297130] unbound[5379:0] debug: subnetcache[module 0] operate: extstate:module_wait_module event:module_event_moddone
[1730297130] unbound[5379:0] info: subnetcache operate: query google.com. A IN
[1730297130] unbound[5379:0] debug: cache memory msg=78333 rrset=133364 infra=41492 val=69414 subnet=74536

这是我第二个问题的后续问题。@mpboden 的解决方案已实施。此外，我添加了auto-trust-anchor-file:和启用remote-control:，如未绑定示例中为其余网络示例设置所定义。

server:
    directory: "/etc/unbound"
    username: "unbound"
    chroot: ""
    verbosity: 1
    logfile: "/etc/unbound/unbound.log"
    pidfile: "/etc/unbound/unbound.pid"
    # location of the trust anchor file that enables DNSSEC
    auto-trust-anchor-file: "/var/lib/unbound/root.key"
    # send minimal amount of information to upstream servers to enhance privacy
    qname-minimisation: yes
    # The port number on which the server responds to queries. 
    port: 3000
    # the interface that is used to connect to the network (this will listen to all interfaces)
    interface: 0.0.0.0
    interface: ::0
    # addresses from the IP range that are allowed to connect to the resolver
    access-control: 192.168.1.0/24 allow
    access-control: 2001:DB8::/64 allow

remote-control:
    # allows controling unbound using "unbound-control"
    control-enable: yes

但是，我在调试模式下发现了 4 个错误和 1 个失败消息。通过我的故障排除工作，我发现这些错误和失败消息在control-enable: yes允许的情况下发生。

root@DNS:/etc/unbound# unbound -d -vv -c unbound.conf
[1730259092] unbound[6165:0] notice: Start of unbound 1.19.2.
[1730259092] unbound[6165:0] error: Error for server-cert-file: /etc/unbound/unbound_server.pem
[1730259092] unbound[6165:0] error: Error in SSL_CTX use_certificate_chain_file crypto error:80000002:system library::No such file or directory
[1730259092] unbound[6165:0] error: and additionally crypto error:10080002:BIO routines::system lib
[1730259092] unbound[6165:0] error: and additionally crypto error:0A080002:SSL routines::system lib
[1730259092] unbound[6165:0] fatal error: could not set up remote-control

我已检查过是否/var/lib/unbound/root.key存在。Unbound 仍可工作但unbound-control无法使用。Unbound 正在寻找/etc/unbound/unbound_server.pem但该文件不存在。我该如何解决此远程控制配置问题？

更新：

通过@mpboden的回答，我发现该命令unbound-control-setup旨在在 /etc/unbound 中创建这些文件：unbound_control.pem，，，， 以允许远程控制。unbound_server.pemunbound_control.keyunbound_server.key

root@DNS:/etc/unbound# unbound-control-setup -h
usage: /usr/sbin/unbound-control-setup OPTIONS
OPTIONS
-d <dir>  used directory to store keys and certificates (default: /etc/unbound)
-h        show help notice
-r        recreate certificates
root@DNS:/etc/unbound# unbound-control-setup
setup in directory /etc/unbound
Certificate request self-signature ok
subject=CN = unbound-control
removing artifacts
Setup success. Certificates created. Enable in unbound.conf file to use
root@DNS:/etc/unbound# ls
unbound.conf    unbound.conf.d       unbound.pid          unbound_control.pem  unbound_server.pem
unbound.log     unbound_control.key  unbound_server.key

这是我之前问题的后续问题。以下是/etc/unbound/unbound.conf文件：

# unbound.conf(5) config file for unbound(8).
server:
    directory: "/etc/unbound"
    username: "unbound"
    chroot: ""
    logfile: "/etc/unbound/unbound.log"
    pidfile: "/etc/unbound/unbound.pid"
    verbosity: 1
    # listen on all interfaces and answer queries from the local port 3000.
    interface: 0.0.0.0 
    interface: ::0
    port: 3000
    access-control: 10.0.0.0/8 allow
    #access-control: 2001:DB8::/64 allow

开始时unbound.service，我尝试dig通过本地未绑定的服务器访问域：

root@DNS:/etc/unbound# dig example.com A @192.168.1.50 -p 3000

; <<>> DiG 9.18.28-0ubuntu0.24.04.1-Ubuntu <<>> example.com A @192.168.1.50 -p 3000
;; global options: +cmd
;; Got answer:
;; ->>HEADER<<- opcode: QUERY, status: REFUSED, id: 8367
;; flags: qr rd ad; QUERY: 0, ANSWER: 0, AUTHORITY: 0, ADDITIONAL: 0
;; WARNING: recursion requested but not available

;; Query time: 0 msec
;; SERVER: 192.168.1.50#3000(192.168.1.50) (UDP)
;; WHEN: Tue Oct 29 16:18:19 UTC 2024
;; MSG SIZE  rcvd: 12

我不明白为什么 WARNING: recursion requested but not availableunbound 默认配置为递归解析器。另外。SERVER: 192.168.1.50#3000(192.168.1.50) (UDP)显示使用了 unbound，但无法获取域。哪里出了问题，如何修复此问题？

下面显示了通过存根服务器的答案systemd-resolved.service：

root@DNS:/etc/unbound# dig example.com

; <<>> DiG 9.18.28-0ubuntu0.24.04.1-Ubuntu <<>> example.com
;; global options: +cmd
;; Got answer:
;; ->>HEADER<<- opcode: QUERY, status: NOERROR, id: 36356
;; flags: qr rd ra; QUERY: 1, ANSWER: 1, AUTHORITY: 0, ADDITIONAL: 1

;; OPT PSEUDOSECTION:
; EDNS: version: 0, flags:; udp: 65494
;; QUESTION SECTION:
;example.com.           IN  A

;; ANSWER SECTION:
example.com.        3304    IN  A   93.184.215.14

;; Query time: 12 msec
;; SERVER: 127.0.0.53#53(127.0.0.53) (UDP)
;; WHEN: Tue Oct 29 16:43:59 UTC 2024
;; MSG SIZE  rcvd: 56

更新：

按照 @mpboden 的回答纠正子网后，该dig命令仅起作用一次。为什么会这样？

root@DNS:/etc/unbound/unbound.conf.d# systemctl start unbound.service
root@DNS:/etc/unbound/unbound.conf.d# [1730230920] unbound[5780:0] notice: init module 0: subnetcache
[1730230920] unbound[5780:0] notice: init module 1: validator
[1730230920] unbound[5780:0] notice: init module 2: iterator
[1730230921] unbound[5780:0] info: start of service (unbound 1.19.2).

root@DNS:/etc/unbound/unbound.conf.d# dig example.com A @192.168.1.50 -p 3000

; <<>> DiG 9.18.28-0ubuntu0.24.04.1-Ubuntu <<>> example.com A @192.168.1.50 -p 3000
;; global options: +cmd
;; Got answer:
;; ->>HEADER<<- opcode: QUERY, status: NOERROR, id: 40273
;; flags: qr rd ra; QUERY: 1, ANSWER: 1, AUTHORITY: 0, ADDITIONAL: 1

;; OPT PSEUDOSECTION:
; EDNS: version: 0, flags:; udp: 1232
;; QUESTION SECTION:
;example.com.           IN  A

;; ANSWER SECTION:
example.com.        3600    IN  A   93.184.215.14

;; Query time: 712 msec
;; SERVER: 192.168.1.50#3000(192.168.1.50) (UDP)
;; WHEN: Tue Oct 29 19:42:34 UTC 2024
;; MSG SIZE  rcvd: 56

root@DNS:/etc/unbound/unbound.conf.d# dig google.com A @192.168.1.50 -p 3000

; <<>> DiG 9.18.28-0ubuntu0.24.04.1-Ubuntu <<>> google.com A @192.168.1.50 -p 3000
;; global options: +cmd
;; Got answer:
;; ->>HEADER<<- opcode: QUERY, status: REFUSED, id: 49774
;; flags: qr rd ad; QUERY: 0, ANSWER: 0, AUTHORITY: 0, ADDITIONAL: 0
;; WARNING: recursion requested but not available

;; Query time: 0 msec
;; SERVER: 192.168.1.50#3000(192.168.1.50) (UDP)
;; WHEN: Tue Oct 29 19:42:56 UTC 2024
;; MSG SIZE  rcvd: 12


root@DNS:/etc/unbound/unbound.conf.d# dig example.com A @192.168.1.50 -p 3000

; <<>> DiG 9.18.28-0ubuntu0.24.04.1-Ubuntu <<>> example.com A @192.168.1.50 -p 3000
;; global options: +cmd
;; Got answer:
;; ->>HEADER<<- opcode: QUERY, status: REFUSED, id: 46236
;; flags: qr rd ad; QUERY: 0, ANSWER: 0, AUTHORITY: 0, ADDITIONAL: 0
;; WARNING: recursion requested but not available

;; Query time: 0 msec
;; SERVER: 192.168.1.50#3000(192.168.1.50) (UDP)
;; WHEN: Tue Oct 29 19:43:36 UTC 2024
;; MSG SIZE  rcvd: 12

unbound.service使用以下 3 个默认文件（安装 unbound 后创建）时，运行无错误：

root@DNS:/etc/unbound# cat unbound.conf
# Unbound configuration file for Debian.
#
# See the unbound.conf(5) man page.
#
# See /usr/share/doc/unbound/examples/unbound.conf for a commented
# reference config file.
#
# The following line includes additional configuration files from the
# /etc/unbound/unbound.conf.d directory.
include-toplevel: "/etc/unbound/unbound.conf.d/*.conf"
root@DNS:/etc/unbound# cat unbound.conf.d/remote-control.conf 
remote-control:
  control-enable: yes
  # by default the control interface is is 127.0.0.1 and ::1 and port 8953
  # it is possible to use a unix socket too
  control-interface: /run/unbound.ctl
root@DNS:/etc/unbound# cat unbound.conf.d/root-auto-trust-anchor-file.conf 
server:
    # The following line will configure unbound to perform cryptographic
    # DNSSEC validation using the root trust anchor.
    auto-trust-anchor-file: "/var/lib/unbound/root.key"

然而，当这 3 个文件被删除，并且内容/etc/unbound/unbound.conf包含

# unbound.conf(5) config file for unbound(8).
server:
    directory: "/etc/unbound"
    username: "unbound"
    # make sure unbound can access entropy from inside the chroot.
    # e.g. on linux the use these commands (on BSD, devfs(8) is used):
    #      mount --bind -n /dev/urandom /etc/unbound/dev/urandom
    # and  mount --bind -n /dev/log /etc/unbound/dev/log
    #chroot: "/etc/unbound"
    # logfile: "/etc/unbound/unbound.log"  #uncomment to use logfile.
    pidfile: "/etc/unbound/unbound.pid"
    # verbosity: 1      # uncomment and increase to get more logging.
    # listen on all interfaces, answer queries from the local subnet.
    interface: 0.0.0.0
    interface: ::0
    access-control: 10.0.0.0/8 allow
    #access-control: 2001:DB8::/64 allow

unbound.service无法使用 重启service unbound restart。例如

root@DNS:/etc/unbound# service unbound restart
Job for unbound.service failed because the control process exited with error code.
See "systemctl status unbound.service" and "journalctl -xeu unbound.service" for details.
root@DNS:/etc/unbound# systemctl status unbound.service
× unbound.service - Unbound DNS server
     Loaded: loaded (/usr/lib/systemd/system/unbound.service; disabled; preset: enabled)
     Active: failed (Result: exit-code) since Mon 2024-10-28 16:01:59 UTC; 18s ago
   Duration: 50min 13.453s
       Docs: man:unbound(8)
    Process: 3385 ExecStartPre=/usr/libexec/unbound-helper chroot_setup (code=exited, status=0/SUCCESS)
    Process: 3388 ExecStartPre=/usr/libexec/unbound-helper root_trust_anchor_update (code=exited, status=0/SUCCESS)
    Process: 3391 ExecStart=/usr/sbin/unbound -d -p $DAEMON_OPTS (code=exited, status=1/FAILURE)
    Process: 3393 ExecStopPost=/usr/libexec/unbound-helper chroot_teardown (code=exited, status=0/SUCCESS)
   Main PID: 3391 (code=exited, status=1/FAILURE)
        CPU: 168ms

Oct 28 16:01:59 DNS systemd[1]: unbound.service: Scheduled restart job, restart counter is at 5.
Oct 28 16:01:59 DNS systemd[1]: unbound.service: Start request repeated too quickly.
Oct 28 16:01:59 DNS systemd[1]: unbound.service: Failed with result 'exit-code'.
Oct 28 16:01:59 DNS systemd[1]: Failed to start unbound.service - Unbound DNS server.

为了排除故障，我注释掉了每一行，然后取消注释每一行，直到unbound.service无法重新启动。我发现该行interface: 0.0.0.0是导致错误的原因。我不明白为什么0.0.0.0会导致这个问题。为什么这个 IP 地址会导致这个问题？

系统：

• 未绑定版本：1.19.2
• 操作系统：Linux DNS 6.1.63 #218 SMP 星期四 11 月 30 日 20:48:04 CST 2023 aarch64 aarch64 aarch64 GNU/Linux 于 Ubuntu Server 24.04.1
• unbound -V输出：

root@DNS::/etc/unbound# unbound -V
Version 1.19.2

Configure line: --build=aarch64-linux-gnu --prefix=/usr --includedir=${prefix}/include --mandir=${prefix}/share/man --infodir=${prefix}/share/info --sysconfdir=/etc --localstatedir=/var --disable-option-checking --disable-silent-rules --libdir=${prefix}/lib/aarch64-linux-gnu --runstatedir=/run --disable-maintainer-mode --disable-dependency-tracking --with-pythonmodule --with-pyunbound --enable-subnet --enable-dnstap --enable-systemd --enable-cachedb --with-libhiredis --with-libnghttp2 --with-chroot-dir= --with-dnstap-socket-path=/run/dnstap.sock --disable-rpath --with-pidfile=/run/unbound.pid --with-libevent --enable-tfo-client --with-rootkey-file=/usr/share/dns/root.key --disable-flto --enable-tfo-server
Linked libs: libevent 2.1.12-stable (it uses epoll), OpenSSL 3.0.13 30 Jan 2024
Linked modules: dns64 python cachedb subnetcache respip validator iterator
TCP Fastopen feature available


BSD licensed, see LICENSE in source package for details.
Report bugs to [email protected] or https://github.com/NLnetLabs/unbound/issues

更新：

root@DNS:/etc/unbound# unbound -d -vv -c /etc/unbound/unbound.conf
[1730176049] unbound[4263:0] notice: Start of unbound 1.19.2.
[1730176049] unbound[4263:0] error: can't bind socket: Address already in use for 0.0.0.0 port 53
[1730176049] unbound[4263:0] fatal error: could not open ports

当我执行时dig example.com，返回的其中一行显示：

;; SERVER: 127.0.0.53#53(127.0.0.53) (UDP)

你能解释一下这一行中每个部分的含义吗？

我注意到 Ubuntu 24.04 中的 Nautilus 在复制大量文件时不显示进度盘。这种情况是我独有的还是存在错误或此功能已被删除？Ubuntu 22.04 中的 Nautilus 确实显示了此复制进度盘。

回复@cordlord的回答：

下图说明了我对您的回答的评论中的意思。与在一个窗口中使用多个选项卡相比，此方法的好处是两个文件夹中的内容可同时显示。

下图显示了 nautilus 窗口未处于紧凑模式时的菜单栏。正如您在回答中提到的，复制进度信息显示在左侧菜单栏的底部。

从 22.04升级到 24.04 时do-release-upgrade，此系统在重启时遇到问题（即安装 24.04 完成后）。我该如何解决此问题？升级过程由nixCraft提供。

以下是EFI启动画面：

Document Scanner我正在尝试通过佳能 E4570 扫描仪打印机的顶部进纸器使用该应用程序进行双面复印。

下图是点击 之前的应用程序设置Scan。应用程序可以扫描纸张的顶页，但不能扫描纸张的底页。如何激活双面扫描？

系统和应用程序信息：

• 系统：Linux 6.8.0-40-generic#40~22.04.3-Ubuntu
• 佳能固件：1.070
• 文档扫描仪：42.0

下载并解压 libreoffice 并访问后~/Downloads/tmp/LibreOffice_24.2.3.2_Linux_x86-64_deb/DEB，我遇到了这个问题。如何在 Ubuntu 22.04 上克服它们？我无法安装任何这些文件。

$ ls
libobasis24.2-base_24.2.3.2-2_amd64.deb                                  libobasis24.2-images_24.2.3.2-2_amd64.deb                  libobasis24.2-xsltfilter_24.2.3.2-2_amd64.deb
libobasis24.2-calc_24.2.3.2-2_amd64.deb                                  libobasis24.2-impress_24.2.3.2-2_amd64.deb                 libreoffice24.2_24.2.3.2-2_amd64.deb
libobasis24.2-core_24.2.3.2-2_amd64.deb                                  libobasis24.2-kde-integration_24.2.3.2-2_amd64.deb         libreoffice24.2-base_24.2.3.2-2_amd64.deb
libobasis24.2-draw_24.2.3.2-2_amd64.deb                                  libobasis24.2-librelogo_24.2.3.2-2_amd64.deb               libreoffice24.2-calc_24.2.3.2-2_amd64.deb
libobasis24.2-en-us_24.2.3.2-2_amd64.deb                                 libobasis24.2-libreofficekit-data_24.2.3.2-2_amd64.deb     libreoffice24.2-debian-menus_24.2.3-2_all.deb
libobasis24.2-extension-beanshell-script-provider_24.2.3.2-2_amd64.deb   libobasis24.2-math_24.2.3.2-2_amd64.deb                    libreoffice24.2-dict-en_24.2.3.2-2_amd64.deb
libobasis24.2-extension-javascript-script-provider_24.2.3.2-2_amd64.deb  libobasis24.2-ogltrans_24.2.3.2-2_amd64.deb                libreoffice24.2-dict-es_24.2.3.2-2_amd64.deb
libobasis24.2-extension-mediawiki-publisher_24.2.3.2-2_amd64.deb         libobasis24.2-onlineupdate_24.2.3.2-2_amd64.deb            libreoffice24.2-dict-fr_24.2.3.2-2_amd64.deb
libobasis24.2-extension-nlpsolver_24.2.3.2-2_amd64.deb                   libobasis24.2-ooofonts_24.2.3.2-2_amd64.deb                libreoffice24.2-draw_24.2.3.2-2_amd64.deb
libobasis24.2-extension-pdf-import_24.2.3.2-2_amd64.deb                  libobasis24.2-ooolinguistic_24.2.3.2-2_amd64.deb           libreoffice24.2-en-us_24.2.3.2-2_amd64.deb
libobasis24.2-extension-report-builder_24.2.3.2-2_amd64.deb              libobasis24.2-postgresql-sdbc_24.2.3.2-2_amd64.deb         libreoffice24.2-impress_24.2.3.2-2_amd64.deb
libobasis24.2-firebird_24.2.3.2-2_amd64.deb                              libobasis24.2-python-script-provider_24.2.3.2-2_amd64.deb  libreoffice24.2-math_24.2.3.2-2_amd64.deb
libobasis24.2-gnome-integration_24.2.3.2-2_amd64.deb                     libobasis24.2-pyuno_24.2.3.2-2_amd64.deb                   libreoffice24.2-ure_24.2.3.2-2_amd64.deb
libobasis24.2-graphicfilter_24.2.3.2-2_amd64.deb                         libobasis24.2-writer_24.2.3.2-2_amd64.deb                  libreoffice24.2-writer_24.2.3.2-2_amd64.deb

$ sudo dpkg -i libreoffice24.2-base_24.2.3.2-2_amd64.deb 
Selecting previously unselected package libreoffice24.2-base.
(Reading database ... 520086 files and directories currently installed.)
Preparing to unpack libreoffice24.2-base_24.2.3.2-2_amd64.deb ...
Unpacking libreoffice24.2-base (24.2.3.2-2) ...
dpkg: dependency problems prevent configuration of libreoffice24.2-base:
 libreoffice24.2-base depends on libreoffice24.2 (>= 24.2.3.2); however:
  Package libreoffice24.2 is not installed.
 libreoffice24.2-base depends on libreoffice24.2 (<= 24.2.3.2-2); however:
  Package libreoffice24.2 is not installed.
 libreoffice24.2-base depends on libobasis24.2-base (>= 24.2.3.2); however:
  Package libobasis24.2-base is not installed.
 libreoffice24.2-base depends on libobasis24.2-base (<= 24.2.3.2-2); however:
  Package libobasis24.2-base is not installed.

dpkg: error processing package libreoffice24.2-base (--install):
 dependency problems - leaving unconfigured
Errors were encountered while processing:
 libreoffice24.2-base

笔记

如果您想要requirements.txt锁定文件的输出，请运行 $ pipenv lock -r。然而，这将包括所有哈希值（这太棒了！）。要获得requirements.txt不带哈希值的 a，请使用 $ pipenv run pip freeze.

根据上面的pipelinev 通知，如果您想要requirements.txt锁定文件的输出，您应该运行$ pipenv lock -r. 但是，-r选项不存在：

$ pipenv lock -r
Usage: pipenv lock [OPTIONS]
Try 'pipenv lock -h' for help.
$ pipenv lock -h
Usage: pipenv lock [OPTIONS]

  Generates Pipfile.lock.

Options:
  --categories TEXT
  --dev-only             Emit development dependencies *only* (overrides
                         --dev)
  -d, --dev              Generate both develop and default requirements  [env
                         var: PIPENV_DEV]
  --extra-pip-args TEXT
  --pre                  Allow pre-releases.
  --python TEXT          Specify which version of Python virtualenv should
                         use.
  --clear                Clears caches (pipenv, pip).  [env var: PIPENV_CLEAR]
  -q, --quiet            Quiet mode.
  -v, --verbose          Verbose mode.
  --pypi-mirror TEXT     Specify a PyPI mirror.
  -h, --help             Show this message and exit.

requirements.txt我可以知道获取pipelinev 锁定文件输出的命令吗？

我想要在之前通过 apt、snap 和 flatpak 安装 Openshot 的计算机上使用最新的 Linux（64 位 AppImage）文件全新安装 Openshot。我已经清除了所有旧的安装。我什至已经清除了 Flatpak。不过，我仍然在这台机器上找到了 Openshot 文件，并且其缩略图出现在 Ubuntu 22.04 应用程序网格中。

$ sudo apt list | grep openshot

WARNING: apt does not have a stable CLI interface. Use with caution in scripts.

libopenshot-audio-dev/jammy 0.2.0+dfsg1-4 amd64
libopenshot-audio-doc/jammy,jammy 0.2.0+dfsg1-4 all
libopenshot-audio-test-sound/jammy 0.2.0+dfsg1-4 amd64
libopenshot-audio7/jammy 0.2.0+dfsg1-4 amd64
libopenshot-dev/jammy 0.2.5+dfsg1-6build2 amd64
libopenshot-doc/jammy,jammy 0.2.5+dfsg1-6build2 all
libopenshot19/jammy 0.2.5+dfsg1-6build2 amd64
openshot-qt-doc/jammy,jammy 2.5.1+dfsg1-2 all
openshot-qt/jammy,jammy 2.5.1+dfsg1-2 all
python3-openshot/jammy 0.2.5+dfsg1-6build2 amd64

$ sudo apt purge openshot
Reading package lists... Done
Building dependency tree... Done
Reading state information... Done
Package 'openshot' is not installed, so not removed
The following packages were automatically installed and are no longer required:
  libappstream-glib8 libmalcontent-0-0 libostree-1-1
Use 'sudo apt autoremove' to remove them.
0 upgraded, 0 newly installed, 0 to remove and 1 not upgraded.

$ sudo apt purge openshot-qt
Reading package lists... Done
Building dependency tree... Done
Reading state information... Done
Package 'openshot-qt' is not installed, so not removed
The following packages were automatically installed and are no longer required:
  libappstream-glib8 libmalcontent-0-0 libostree-1-1
Use 'sudo apt autoremove' to remove them.
0 upgraded, 0 newly installed, 0 to remove and 1 not upgraded.

$ dpkg -l | grep openshot

$ flatpak
bash: /usr/bin/flatpak: No such file or directory

然而，根据Nautilus的说法，该/var/lib/flatpak/app目录中存在许多残留文件。

此外，Openshot 缩略图继续存在于“应用程序”网格中

但文件夹~/.local/share/applications中/usr/share/applications不包含任何 openshot.desktop文件。

问题：

1. 我可以直接删除该文件夹/var/lib/flatpak/app/org.openshot.OpenShot而不会对机器造成任何问题吗？
2. 既然我已经清除了 flatpak，我什至可以删除文件夹吗/var/lib/flatpak？
3. 另外，如何删除应用程序网格中的 Openshot 缩略图？

更新：

我发现存在一个名为org.openshot.OpenShot.desktop. 它的路径是：

• /var/lib/flatpak/app/org.openshot.OpenShot/x86_64/stable/a3e062afc67b6bcba4c61fffa4a9c7d4baab1fb0843f99b8f79e2497e15bc42e/export/share/applications/org.openshot.OpenShot.desktop
• /var/lib/flatpak/exports/share/applications/org.openshot.OpenShot.desktop

此终端命令从应用程序网格中删除了 Openshot 缩略图：

sudo rm /var/lib/flatpak/exports/share/applications/org.openshot.OpenShot.desktop

按PrtScrn并进入视频模式录制桌面视频后，录制的视频显示以下问题：

如何解决此Screencast视频模式录制问题？Screencast 可以拍摄桌面照片，但无法在桌面上录制视频。

系统详细信息：

乌班图22.04

宏碁 E14 笔记本电脑。

Linux 6.2.0-35-通用

供参考：

1. Cheese 应用程序也无法运行，但 Guvcview 应用程序可以运行。
2. Zoom 应用程序开箱即用。

$ dpkg -l | grep softwar
ii  brltty                                        6.4-4ubuntu3                                amd64        Access software for a blind person using a braille display
ii  docbook-xml                                   4.5-11                                      all          standard XML documentation system for software and systems
ii  espeak-ng-data:amd64                          1.50+dfsg-10                                amd64        Multi-lingual software speech synthesizer: speech data files
ii  gnome-software                                41.5-2ubuntu2                               amd64        Software Center for GNOME
ii  gnome-software-common                         41.5-2ubuntu2                               all          Software Center for GNOME (common files)
ii  gnome-software-plugin-flatpak                 41.5-2ubuntu2                               amd64        Flatpak support for GNOME Software
ii  gnome-software-plugin-snap                    41.5-2ubuntu2                               amd64        Snap support for GNOME Software
ii  libdv4:amd64                                  1.0.0-14build1                              amd64        software library for DV format digital video (runtime lib)
ii  libespeak-ng1:amd64                           1.50+dfsg-10                                amd64        Multi-lingual software speech synthesizer: shared library
ii  libfluidsynth-dev:amd64                       2.2.5-1                                     amd64        Real-time MIDI software synthesizer (development files)
ii  libfluidsynth3:amd64                          2.2.5-1                                     amd64        Real-time MIDI software synthesizer (runtime library)
ii  libqpdf28:amd64                               10.6.3-1                                    amd64        runtime library for PDF transformation/inspection software
ii  libwildmidi2:amd64                            0.4.3-1                                     amd64        software MIDI player library
ii  python3-software-properties                   0.99.22.7                                   all          manage the repositories that you install software from
ii  software-properties-common                    0.99.22.7                                   all          manage the repositories that you install software from (common)
ii  software-properties-gtk                       0.99.22.7                                   all          manage the repositories that you install software from (gtk)
ii  steam:i386                                    1:1.0.0.74-1ubuntu2                         i386         Valve's Steam digital software delivery system
ii  xbrlapi                                       6.4-4ubuntu3                                amd64        Access software for a blind person using a braille display - xbrlapi

上图显示了 Ubuntu 22.04 系统有两种类型的软件更新文件。即：

1. gnome-software, gnome-software-common, gnome-software-plugin-flatpak,gnome-software-plugin-snap
2. python3-software-properties,software-properties-common和software-properties-gtk

在扩展坞上，存在这两个应用程序图标（见下文）。这两个程序执行相同的工作。

我认为只需要其中之一是否正确？我应该卸载哪些程序以避免系统中存在重复的程序？

我该如何解决这个sudo apt update错误？

Err:9 http://download.opensuse.org/repositories/home:/pzz/xUbuntu_20.04  InRelease
  The following signatures were invalid: EXPKEYSIG 23E07629B9E3C9E4 home:pzz OBS Project <home:[email protected]>
Fetched 2,441 B in 3s (819 B/s)
Reading package lists... Done
Building dependency tree       
Reading state information... Done
19 packages can be upgraded. Run 'apt list --upgradable' to see them.
W: An error occurred during the signature verification. The repository is not updated and the previous index files will be used. GPG error: http://download.opensuse.org/repositories/home:/pzz/xUbuntu_20.04  InRelease: The following signatures were invalid: EXPKEYSIG 23E07629B9E3C9E4 home:pzz OBS Project <home:[email protected]>
W: Failed to fetch http://download.opensuse.org/repositories/home:/pzz/xUbuntu_20.04/InRelease  The following signatures were invalid: EXPKEYSIG 23E07629B9E3C9E4 home:pzz OBS Project <home:[email protected]>
W: Some index files failed to download. They have been ignored, or old ones used instead.

我已经尝试过帖子中的解决方案 如何修复 GPG 错误“NO_PUBKEY”？但他们没有工作：

$ sudo apt-key adv --keyserver keyserver.ubuntu.com --recv-keys 23E07629B9E3C9E4
[sudo] password for master: 
Executing: /tmp/apt-key-gpghome.QYq1pmnpyE/gpg.1.sh --keyserver keyserver.ubuntu.com --recv-keys 23E07629B9E3C9E4
gpg: keyserver receive failed: Server indicated a failure
$ gpg --keyserver hkp://keyserver.ubuntu.com:80 --recv ^C
$ 23E07629B9E3C9E4^C
$ gpg --keyserver hkp://keyserver.ubuntu.com:80 --recv 23E07629B9E3C9E4
gpg: keyserver receive failed: No data

在检查安装在系统中的 snap 包时，我注意到一些包有重复，一个具有超过修订号，而另一个具有较新的修订号。对于这样的重复包，我的问题是：

1. 为什么它们是重复的？
2. 我可以删除旧软件包以确保更好的磁盘空间管理吗？
3. 如何删除旧包？

以下是有和没有重复的包的示例：

$ du -hcs /var/lib/snapd/snaps/*
31M /var/lib/snapd/snaps/2048x_3.snap
286M    /var/lib/snapd/snaps/atom_282.snap
4.0K    /var/lib/snapd/snaps/bare_5.snap
72M /var/lib/snapd/snaps/bitwarden_58.snap
72M /var/lib/snapd/snaps/bitwarden_59.snap
196M    /var/lib/snapd/snaps/blender_1113.snap
214M    /var/lib/snapd/snaps/blender_1237.snap
9.1M    /var/lib/snapd/snaps/canonical-livepatch_119.snap
9.1M    /var/lib/snapd/snaps/canonical-livepatch_126.snap
148M    /var/lib/snapd/snaps/chromium_1854.snap
148M    /var/lib/snapd/snaps/chromium_1864.snap
17M /var/lib/snapd/snaps/chromium-ffmpeg_23.snap
18M /var/lib/snapd/snaps/chromium-ffmpeg_24.snap
....

~$ ls -lh /var/lib/snapd/snaps/
total 12G
-rw------- 2 root root  31M Aug  5 06:23 2048x_3.snap
-rw------- 2 root root 286M Aug  5 08:35 atom_282.snap
-rw------- 2 root root 4.0K Sep 22 18:17 bare_5.snap
-rw------- 1 root root  72M Oct 30 00:20 bitwarden_58.snap
-rw------- 1 root root  72M Dec  9 04:28 bitwarden_59.snap
-rw------- 1 root root 196M Nov 18 04:06 blender_1113.snap
-rw------- 1 root root 214M Dec  4 09:39 blender_1237.snap
-rw------- 2 root root 9.1M Nov 17 21:06 canonical-livepatch_119.snap
-rw------- 2 root root 9.1M Nov 22 22:39 canonical-livepatch_126.snap
-rw------- 1 root root 148M Dec 16 04:28 chromium_1854.snap
-rw------- 1 root root 148M Jan  8 08:33 chromium_1864.snap
-rw------- 1 root root  17M Sep  3 06:29 chromium-ffmpeg_23.snap
-rw------- 2 root root  18M Nov 29 14:23 chromium-ffmpeg_24.snap
....

在我正在查看的系统上，使用的总磁盘空间/var/lib/snapd/snaps/*为 12,180.248 MB。所有重复包（即同一包的旧版本）的磁盘空间为 4,163.1 MB。简而言之，较旧的修订包目前占 12,180.248 MB 的 34.18%。这似乎是使用我以前没有意识到的 SNAP 应用程序的成本。

用户如何列出 Ubuntu 20.04 中每个已安装 snap 包的大小？目的是获得每个已安装的 snap 包所使用的磁盘空间的概览。该命令snap list不执行此操作。此外，该应用程序Disk Usage Analyzer无法显示超过/var/lib/snapd/snaps.

我似乎无法让 CUDA 11.5 在 Ubuntu 20.04 + Nvidia 470 驱动程序 + Geforce GTX Titan 上运行。安装此 CUDA 版本并重新启动后，双显示器系统将缩减为仅具有 1920x1080 低分辨率的单显示器系统。此外，似乎安装了非 Nvidia 驱动程序。

我已经检查过这样的系统可以安装 CUDA 11.4，这个 CUDA 版本一切正常。

CUDA 11.5 是否与 Ubuntu 20.04 + Nvidia 470 驱动程序 + Geforce GTX Titan 兼容？

佳能 MG5370 打印机和扫描仪连接到与 Ubuntu 20.04 相同的网络。使用Settings--> Printers--> Add，Ubuntu 20.04 能够检测到这台打印机。但是，当我尝试“测试打印”时，什么也没有发生。

我相信发生这种情况是因为它使用的是通用打印机驱动程序。见下图。

在同一网络中的 Ubuntu 18.04 系统上，这台打印机可以工作，我可以看到它正在使用名为Canon MG5300 series - CUPS+Gutenprint v5.2.13.

要安装此驱动程序，我单击了Gear按钮并选择了Printer Details. 之后，我点击了Search for Drivers。但是，它找不到合适的驱动程序。接下来，我点击了Select from Database-->Canon但找不到任何MG驱动MG5300程序。

我也试过这个解决方案。安装成功，但即使打印机扫描仪通过 USB 连接到系统，也找不到扫描仪。见下文。

以前，我曾询问过为 Ubuntu 16.04 设置同一台打印机的扫描仪。我在那里尝试了解决方案。佳能的安装scangermp也因.

$ sudo ./install.sh
==================================================

ScanGear MP
Version 1.80
Copyright CANON INC. 2007-2011
All Rights Reserved.

==================================================
Command executed = sudo dpkg -iG ./packages/scangearmp-common_1.80-1_amd64.deb
Selecting previously unselected package scangearmp-common.
(Reading database ... 256647 files and directories currently installed.)
Preparing to unpack .../scangearmp-common_1.80-1_amd64.deb ...
Unpacking scangearmp-common (1.80-1) ...
dpkg: dependency problems prevent configuration of scangearmp-common:
 scangearmp-common depends on libpng12-0 (>= 1.2.8rel); however:
  Package libpng12-0 is not installed.
 scangearmp-common depends on libusb-0.1-4 (>= 2:0.1.10a); however:
  Package libusb-0.1-4 is not installed.

dpkg: error processing package scangearmp-common (--install):
 dependency problems - leaving unconfigured
Errors were encountered while processing:
 scangearmp-common
Command executed = sudo dpkg -P scangearmp-common
(Reading database ... 256695 files and directories currently installed.)
Removing scangearmp-common (1.80-1) ...
Purging configuration files for scangearmp-common (1.80-1) ...

我应该怎么做才能在 Ubuntu 20.04 中设置这台佳能 MG5370 打印机扫描仪？我希望能够打印和扫描。

更新：

$ driverless
$ driverless list
DEBUG: Started ippfind (PID 25370)
DEBUG: Started post-processing (PID 25371)
DEBUG: PID 25370 (ippfind) stopped with status 1!
DEBUG: PID 25371 (Post-processing) exited with no errors.

$ lpinfo -v
file cups-brf:/
network beh
network http
network ipp
network lpd
serial serial:/dev/ttyS0?baud=115200
network https
network ipps
direct hp
network socket
direct usb://Canon/MG5300%20series?serial=20EE62&interface=1
direct hpfax
network dnssd://Canon%20MG5300%20series._printer._tcp.local/?uuid=urn:uuid:00000000-0000-1000-8000-8887178XXXXX

遵循@brian_p 答案的结果：

$ scanimage -L
device `pixma:04A91754_20EE62' is a CANON Canon PIXMA MG5300 multi-function peripheral
device `airscan:w1:Canon MG5300 series' is a WSD Canon MG5300 series ip=192.168.1.XXX
$ airscan-disciver
airscan-disciver: command not found
$ airscan-discover
[devices]
$

打印结果：

sudo apt install printer-driver-gutenprint已成功完成。

$ lpinfo -m | grep MG5370
gutenprint.5.3://bjc-PIXMA-MG5370/expert Canon PIXMA MG5370 - CUPS+Gutenprint v5.3.3
$ lpadmin -p MG5370 -v dnssd://Canon%20MG5300%20series._printer._tcp.local/?uuid=urn:uuid:00000000-0000-1000-8000-8887178XXXXX -E -m gutenprint.5.3://bjc-PIXMA-MG5370/expert
lpadmin: Printer drivers are deprecated and will stop working in a future version of CUPS.
$ lp -d MG5370 /etc/nsswitch.conf
request id is MG5370-2 (1 file(s))

无线打印成功。