How to display dependencies for deb package

Use dpkg to pretty print package dependencies.

Extract and simply print dependencies from a package without using dpkg utilities.

$ ar -p postgresql-common_181_all.deb control.tar.gz | \
    tar --to-stdout --gzip --extract --file - ./control | grep Depends:

Depends: adduser, debconf (>= 0.5.00) | debconf-2.0, lsb-base (>= 3.0-3), postgresql-client-common (= 181), procps, ssl-cert (>= 1.0.11), ucf, init-system-helpers (>= 1.18~)

Print dependencies from a package using dpkg utility.

$ dpkg --info postgresql-common_181_all.deb | grep Depends

Depends: adduser, debconf (>= 0.5.00) | debconf-2.0, lsb-base (>= 3.0-3), postgresql-client-common (= 181), procps, ssl-cert (>= 1.0.11), ucf, init-system-helpers (>= 1.18~)

Use dpkg to pretty print package dependencies.

$ dpkg --info postgresql-common_181_all.deb | \
    awk 'BEGIN{print "Depends:"} \
         /Depends: / { gsub("Depends: ", ""); \
                       n=split($0,deps,","); \
                       for(i=1;i<=n;i++) print deps[i] }'

Depends:
 adduser
 debconf (>= 0.5.00) | debconf-2.0
 lsb-base (>= 3.0-3)
 postgresql-client-common (= 181)
 procps
 ssl-cert (>= 1.0.11)
 ucf
 init-system-helpers (>= 1.18~)