$ sudo apt-get install nginx
Reading package lists... Done
Building dependency tree
Reading state information... Done
The following packages were automatically installed and are no longer required:
  apt-tools liboska libsdio
Use 'sudo apt autoremove' to remove them.
The following additional packages will be installed:
  nginx-common nginx-core
Suggested packages:
  fcgiwrap nginx-doc
The following NEW packages will be installed
  nginx nginx-common nginx-core
0 to upgrade, 3 to newly install, 0 to remove and 286 not to upgrade.
Need to get 0 B/460 kB of archives.
After this operation, 1,485 kB of additional disk space will be used.
Do you want to continue? [Y/n] Y
Preconfiguring packages ...
Selecting previously unselected package nginx-common.
(Reading database ... 173338 files and directories currently installed.)a
Preparing to unpack .../nginx-common_1.10.3-0ubuntu0.16.04.5_all.deb ...
Unpacking nginx-common (1.10.3-0ubuntu0.16.04.5) ...
Selecting previously unselected package nginx-core.
Preparing to unpack .../nginx-core_1.10.3-0ubuntu0.16.04.5_amd64.deb ...
Unpacking nginx-core (1.10.3-0ubuntu0.16.04.5) ...
Selecting previously unselected package nginx.
Preparing to unpack .../nginx_1.10.3-0ubuntu0.16.04.5_all.deb ...
Unpacking nginx (1.10.3-0ubuntu0.16.04.5) ...
Processing triggers for systemd (229-4ubuntu21.1) ...
Processing triggers for ureadahead (0.100.0-19) ...
ureadahead will be reprofiled on next reboot
Processing triggers for ufw (0.35-0ubuntu2) ...
Setting up nginx-common (1.10.3-0ubuntu0.16.04.5) ...
Setting up nginx-core (1.10.3-0ubuntu0.16.04.5) ...
Job for nginx.service failed because the control process exited with error code. See "systemctl status nginx.service" and "journalctl -xe" for details.
invoke-rc.d: initscript nginx, action "start" failed.
● nginx.service - A high performance web server and a reverse proxy server
   Loaded: loaded (/lib/systemd/system/nginx.service; enabled; vendor preset: enabled)
   Active: failed (Result: exit-code) since Sat 2021-08-07 10:12:03 IST; 21ms ago
  Process: 1824 ExecStart=/usr/sbin/nginx -g daemon on; master_process on; (code=exited, status=1/FAILURE)
  Process: 1820 ExecStartPre=/usr/sbin/nginx -t -q -g daemon on; master_process on; (code=exited, status=0/SUCCESS)

Aug 07 10:12:02 test-pc nginx[1824]: nginx: [emerg] listen() to [::]:80, backlog 511 failed (98: Address already in use)
Aug 07 10:12:02 test-pc nginx[1824]: nginx: [emerg] listen() to 0.0.0.0:80, backlog 511 failed (98: Address already in use)
Aug 07 10:12:02 test-pc nginx[1824]: nginx: [emerg] listen() to [::]:80, backlog 511 failed (98: Address already in use)
Aug 07 10:12:03 test-pc nginx[1824]: nginx: [emerg] listen() to 0.0.0.0:80, backlog 511 failed (98: Address already in use)
Aug 07 10:12:03 test-pc nginx[1824]: nginx: [emerg] listen() to [::]:80, backlog 511 failed (98: Address already in use)
Aug 07 10:12:03 test-pc nginx[1824]: nginx: [emerg] still could not bind()
Aug 07 10:12:03 test-pc systemd[1]: nginx.service: Control process exited, code=exited status=1
Aug 07 10:12:03 test-pc systemd[1]: Failed to start A high performance web server and a reverse proxy server.
Aug 07 10:12:03 test-pc systemd[1]: nginx.service: Unit entered failed state.
Aug 07 10:12:03 test-pc systemd[1]: nginx.service: Failed with result 'exit-code'.
dpkg: error processing package nginx-core (--configure):
 subprocess installed post-installation script returned error exit status 1
dpkg: dependency problems prevent configuration of nginx:
 nginx depends on nginx-core (>= 1.10.3-0ubuntu0.16.04.5) | nginx-full (>= 1.10.3-0ubuntu0.16.04.5) | nginx-light (>= 1.10.3-0ubuntu0.16.04.5) | nginx-extras (>= 1.10.3-0ubuntu0.16.04.5); however:
  Package nginx-core is not configured yet.
  Package nginx-full is not installed.
  Package nginx-light is not installed.
  Package nginx-extras is not installed.
 nginx depends on nginx-core (<< 1.10.3-0ubuntu0.16.04.5.1~) | nginx-full (<< 1.10.3-0ubuntu0.16.04.5.1~) | nginx-light (<< 1.10.3-0ubuntu0.16.04.5.1~) | nginx-extras (<< 1.10.3-0ubuntu0.16.04.5.1~); however:
  Package nginx-core is not configured yet.
  Package nginx-full is not installed.
  Package nginx-light is not installed.
  Package nginx-extras is not installed.

dpkg: error processing package nginx (--configure):
 dependency problems - leaving unconfigured
Processing triggers for systemd (229-4ubuntu21.1) ...
No apport report written because the error message indicates it's a follow-up error from a previous failure.
                                                                                                            Processing triggers for ureadahead (0.100.0-19) ...
Processing triggers for ufw (0.35-0ubuntu2) ...
Errors were encountered while processing:
 nginx-core
 nginx
E: Sub-process /usr/bin/dpkg returned an error code (1)
test1@test-pc:~$ dpkg -l | grep nginx
iU  nginx                                         1.10.3-0ubuntu0.16.04.5                    all          small, powerful, scalable web/proxy server
ii  nginx-common                                  1.10.3-0ubuntu0.16.04.5                    all          small, powerful, scalable web/proxy server - common files
iF  nginx-core                                    1.10.3-0ubuntu0.16.04.5                    amd64        nginx web/proxy server (core version)