Ubuntu find Dependencies for a package

To find dependencies for a package, run

apt-cache depends PACKAGE_NAME

Example

root@ubuntu-s-4vcpu-8gb-nyc1-01:~# apt-cache depends php7.2
php7.2
 |Depends: libapache2-mod-php7.2
 |Depends: php7.2-fpm
  Depends: php7.2-cgi
  Depends: php7.2-common
root@ubuntu-s-4vcpu-8gb-nyc1-01:~# 

In above example, when you install php7.2, it install “libapache2-mod-php7.2”, that will install Apache web server. I had a server with ngtinx, when i install php7.2 package, apache get installed.

You can also use

apt depends PACKAGE_NAME

To find reverse dependency, run

apt-cache rdepends PACKAGE_NAME

apt-cache
apt