[vc_row][vc_column width=”1/1″][vc_column_text]A typical .deb package relies on other packages to install and operate properly. With package managers such as apt-get and aptitude, you can resolve package dependencies, and have all prerequisites installed automatically.

Suppose for whatever reason, you want to manually resolve package dependencies of a particular package, in which case you need to identify all its dependent packages first.

In the following, I will explain how to check package dependencies on pcDuino Ubuntu.

A command-line tool called apt-rdepends can help you in this case. This tool can recursively check dependencies of .deb package, and list all found package dependencies.

To install apt-rdepends on Ubuntu or Debian:

To show package dependency information of a particular package (e.g., tcpdump), run the command with package name:

Reading package lists... Done
Building dependency tree
Reading state information... Done
tcpdump
  Depends: libc6 (>= 2.7)
  Depends: libpcap0.8 (>= 1.2.1)
  Depends: libssl1.0.0 (>= 1.0.0)
libc6
  Depends: libgcc1
libgcc1
  Depends: gcc-4.6-base (= 4.6.3-1ubuntu5)
  Depends: libc6 (>= 2.15-0ubuntu8)
  PreDepends: multiarch-support
gcc-4.6-base
multiarch-support
  Depends: libc6 (>= 2.13-0ubuntu6)
libpcap0.8
  Depends: libc6 (>= 2.11)
  PreDepends: multiarch-support
libssl1.0.0
  Depends: debconf (>= 0.5)
  Depends: debconf-2.0
  Depends: libc6 (>= 2.15-0ubuntu8)
  Depends: libgcc1 (>= 1:4.4.0)
  Depends: zlib1g (>= 1:1.1.4)
  PreDepends: multiarch-support
debconf
  PreDepends: perl-base (>= 5.6.1-4)
perl-base
  PreDepends: dpkg (>= 1.14.20)
  PreDepends: libc6 (>= 2.11)
dpkg
  PreDepends: coreutils (>= 5.93-1)
  PreDepends: libbz2-1.0
  PreDepends: libc6 (>= 2.11)
  PreDepends: libgcc1 (>= 1:4.4.0)
  PreDepends: libselinux1 (>= 1.32)
  PreDepends: tar (>= 1.23)
  PreDepends: xz-utils
  PreDepends: zlib1g (>= 1:1.1.4)
coreutils
  Depends: dpkg (>= 1.15.4)
  Depends: install-info
  PreDepends: libacl1 (>= 2.2.51-5)
  PreDepends: libattr1 (>= 1:2.4.46-5)
  PreDepends: libc6 (>= 2.15)
  PreDepends: libgcc1 (>= 1:4.4.0)
  PreDepends: libselinux1 (>= 1.32)
. . . .

Visualization of Package Dependencies

The text output of apt-rdepends can be difficult to read due to many recursively defined dependency relationships. That is when visualization can help. apt-rdepends can export package dependency information into a dot file, which can be used by a GUI-based graph editor called dotty to visualize package dependencies in a graph format.

For visualization, first install dotty graph editor tool:

Finally, to visualize package dependencies with dotty:

The visualization result of tcpdump package looks like the following.

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