diff --git a/README.md b/README.md
index a598f98..c37eff8 100644
--- a/README.md
+++ b/README.md
@@ -42,6 +42,7 @@ curl -L https://raw.github.com/alphabetum/hosts/master/hosts \
 Usage:
   hosts
   hosts add <ip> <hostname> [<comment>]
+  hosts block <hostname>
   hosts disable (<ip> | <hostname> | <search string>)
   hosts disabled
   hosts edit
@@ -52,6 +53,7 @@ Usage:
   hosts show (<ip> | <hostname> | <search string>)
   hosts search <search string>
   hosts remove (<ip> | <hostname> | <search string>) [--force]
+  hosts unblock <hostname>
 ```
 
 For full usage, run:
@@ -118,6 +120,15 @@ Print the entire contents of the /etc/hosts file.
 
 Search entries for a given search string.
 
+###### `block <hostname>`
+
+Block a given hostname by adding new entries assigning it to `127.0.0.1` for
+IPv4 and both `fe80::1%lo0` and `::1` for IPv6.
+
+###### `unblock <hostname>`
+
+Unblock a given hostname by removing its entries from the hosts file.
+
 ## Tests
 
 To run the test suite, install [Bats](https://github.com/sstephenson/bats) and
diff --git a/hosts b/hosts
index 975b285..7dcb09f 100755
--- a/hosts
+++ b/hosts
@@ -596,6 +596,7 @@ Version: ${_VERSION}
 Usage:
   ${_ME}
   ${_ME} add <ip> <hostname> [<comment>]
+  ${_ME} block <hostname>
   ${_ME} disable (<ip> | <hostname> | <search string>)
   ${_ME} disabled
   ${_ME} edit
@@ -605,6 +606,7 @@ Usage:
   ${_ME} list [enabled | disabled | <search string>]
   ${_ME} show (<ip> | <hostname> | <search string>)
   ${_ME} remove (<ip> | <hostname> | <search string>) [--force]
+  ${_ME} unblock <hostname>
   ${_ME} -h | --help
   ${_ME} --version
 
@@ -729,6 +731,29 @@ add() {
   fi
 }
 
+# ----------------------------------------------------------------------- block
+
+desc "block" <<HEREDOC
+Usage:
+  $_ME block <hostname>
+
+Description:
+  Block a given hostname by adding new entries assigning it to \`127.0.0.1\`
+  for IPv4 and both \`fe80::1%lo0\` and \`::1\` for IPv6.
+HEREDOC
+block() {
+  if [[ -z "${1}" ]]
+  then
+    ${_ME} help block
+    exit 1
+  fi
+
+  ${_ME} add 127.0.0.1 "${1}"
+  # block IPv6
+  ${_ME} add "fe80::1%lo0" "${1}"
+  ${_ME} add "::1" "${1}"
+}
+
 # --------------------------------------------------------------------- disable
 
 desc "disable" <<HEREDOC
@@ -1124,6 +1149,28 @@ show() {
   fi
 }
 
+# --------------------------------------------------------------------- unblock
+
+desc "unblock" <<HEREDOC
+Usage:
+  $_ME unblock <hostname>
+
+Description:
+  Unblock a given hostname by removing its entries from the hosts file.
+HEREDOC
+unblock() {
+  if [[ -z "${1}" ]]
+  then
+    ${_ME} help unblock
+    exit 1
+  fi
+
+  ${_ME} remove 127.0.0.1 "${1}" --force
+  # unblock IPv6
+  ${_ME} remove "fe80::1%lo0" "${1}" --force
+  ${_ME} remove "::1" "${1}" --force
+}
+
 ###############################################################################
 # Run Program
 ###############################################################################
diff --git a/test/block.bats b/test/block.bats
new file mode 100644
index 0000000..2d69132
--- /dev/null
+++ b/test/block.bats
@@ -0,0 +1,77 @@
+#!/usr/bin/env bats
+
+load test_helper
+
+# `hosts block` #################################################################
+
+@test "\`block\` with no arguments exits with status 1." {
+  run "${_HOSTS}" block
+  printf "\${status}: %s\n" "${status}"
+  printf "\${output}: '%s'\n" "${output}"
+  [[ ${status} -eq 1 ]]
+}
+
+@test "\`block\` with no argument does not change the hosts file." {
+  _original="$(cat "${HOSTS_PATH}")"
+
+  run "${_HOSTS}" block
+  printf "\${status}: %s\n" "${status}"
+  printf "\${output}: '%s'\n" "${output}"
+  [[ "$(cat "${HOSTS_PATH}")" == "${_original}" ]]
+}
+
+@test "\`block\` with no arguments prints help information." {
+  run "${_HOSTS}" block
+  printf "\${status}: %s\n" "${status}"
+  printf "\${output}: '%s'\n" "${output}"
+  [[ "${lines[0]}" == "Usage:" ]]
+  [[ "${lines[1]}" == "  hosts block <hostname>" ]]
+}
+
+# `hosts block <hostname>` #################################################
+
+@test "\`block <hostname>\` exits with status 0." {
+  run "${_HOSTS}" block example.com
+  printf "\${status}: %s\n" "${status}"
+  printf "\${output}: '%s'\n" "${output}"
+  [[ ${status} -eq 0 ]]
+}
+
+@test "\`block <hostname>\` adds entries to the hosts file." {
+  _original="$(cat "${HOSTS_PATH}")"
+
+  run "${_HOSTS}" block example.com
+  printf "\${status}: %s\n" "${status}"
+  printf "\${output}: '%s'\n" "${output}"
+  _compare "${_original}" "$(cat "${HOSTS_PATH}")"
+  _compare '127.0.0.1	example.com' "$(sed -n '11p' "${HOSTS_PATH}")"
+  [[ "$(cat "${HOSTS_PATH}")" != "${_original}" ]]
+  [[ "$(sed -n '11p' "${HOSTS_PATH}")" == "127.0.0.1	example.com" ]]
+}
+
+@test "\`block <hostname>\` prints feedback." {
+  run "${_HOSTS}" block example.com
+  printf "\${status}: %s\n" "${status}"
+  printf "\${output}: '%s'\n" "${output}"
+  [[ "${lines[0]}" == "Added:" ]]
+  [[ "${lines[1]}" == "127.0.0.1	example.com" ]]
+  [[ "${lines[2]}" == "Added:" ]]
+  [[ "${lines[3]}" == "fe80::1%lo0	example.com" ]]
+  [[ "${lines[4]}" == "Added:" ]]
+  [[ "${lines[5]}" == "::1	example.com" ]]
+}
+
+# help ########################################################################
+
+@test "\`help block\` exits with status 0." {
+  run "${_HOSTS}" help block
+  [[ ${status} -eq 0 ]]
+}
+
+@test "\`help block\` prints help information." {
+  run "${_HOSTS}" help block
+  printf "\${status}: %s\n" "${status}"
+  printf "\${output}: '%s'\n" "${output}"
+  [[ "${lines[0]}" == "Usage:" ]]
+  [[ "${lines[1]}" == "  hosts block <hostname>" ]]
+}
diff --git a/test/unblock.bats b/test/unblock.bats
new file mode 100644
index 0000000..a179ef9
--- /dev/null
+++ b/test/unblock.bats
@@ -0,0 +1,149 @@
+#!/usr/bin/env bats
+
+load test_helper
+
+# `hosts unblock` #################################################################
+
+@test "\`unblock\` with no arguments exits with status 1." {
+  run "${_HOSTS}" unblock
+  printf "\${status}: %s\n" "${status}"
+  printf "\${output}: '%s'\n" "${output}"
+  [[ ${status} -eq 1 ]]
+}
+
+@test "\`unblock\` with no argument does not change the hosts file." {
+  _original="$(cat "${HOSTS_PATH}")"
+
+  run "${_HOSTS}" unblock
+  printf "\${status}: %s\n" "${status}"
+  printf "\${output}: '%s'\n" "${output}"
+  [[ "$(cat "${HOSTS_PATH}")" == "${_original}" ]]
+}
+
+@test "\`unblock\` with no arguments prints help information." {
+  run "${_HOSTS}" unblock
+  printf "\${status}: %s\n" "${status}"
+  printf "\${output}: '%s'\n" "${output}"
+  [[ "${lines[0]}" == "Usage:" ]]
+  [[ "${lines[1]}" == "  hosts unblock <hostname>" ]]
+}
+
+# `hosts unblock <invalid>` ############################################
+
+@test "\`unblock <invalid> \` exits with status 1." {
+  {
+    run "${_HOSTS}" block example.com
+  }
+
+  run "${_HOSTS}" unblock example.net
+  printf "\${status}: %s\n" "${status}"
+  printf "\${output}: '%s'\n" "${output}"
+  [[ ${status} -eq 1 ]]
+}
+
+@test "\`unblock <invalid>\` prints error message." {
+  {
+    run "${_HOSTS}" block example.com
+  }
+
+  run "${_HOSTS}" unblock example.net
+  printf "\${status}: %s\n" "${status}"
+  printf "\${output}: '%s'\n" "${output}"
+  [[ ${output} == "No matching records found." ]]
+}
+
+# `hosts unblock <hostname>` ###########################################
+
+@test "\`unblock <hostname>\` exits with status 0." {
+  {
+    run "${_HOSTS}" add 0.0.0.0 example.com
+    run "${_HOSTS}" block example.com
+    run "${_HOSTS}" add 127.0.0.1 example.net
+  }
+
+  run "${_HOSTS}" unblock example.com
+  printf "\${status}: %s\n" "${status}"
+  printf "\${output}: '%s'\n" "${output}"
+  [[ ${status} -eq 0 ]]
+}
+
+@test "\`unblock <hostname>\` updates the hosts file." {
+  {
+    run "${_HOSTS}" add 0.0.0.0 example.com
+    run "${_HOSTS}" block example.com
+    run "${_HOSTS}" add 127.0.0.1 example.net
+  }
+  _original="$(cat "${HOSTS_PATH}")"
+
+  run "${_HOSTS}" unblock example.com
+  printf "\${status}: %s\n" "${status}"
+  printf "\${output}: '%s'\n" "${output}"
+  _compare "${_original}" "$(cat "${HOSTS_PATH}")"
+  [[ "$(sed -n '11p' "${HOSTS_PATH}")" == "0.0.0.0	example.com" ]]
+  [[ "$(sed -n '12p' "${HOSTS_PATH}")" == "127.0.0.1	example.net" ]]
+  [[ "$(sed -n '13p' "${HOSTS_PATH}")" == "" ]]
+}
+
+@test "\`unblock <hostname>\` removes all matches." {
+  {
+    run "${_HOSTS}" add 0.0.0.0 example.com
+    run "${_HOSTS}" block example.com
+    run "${_HOSTS}" add 127.0.0.1 example.net
+  }
+  _original="$(cat "${HOSTS_PATH}")"
+
+  run "${_HOSTS}" unblock example.com
+  printf "\${status}: %s\n" "${status}"
+  printf "\${output}: '%s'\n" "${output}"
+  _expected="\
+##
+# Host Database
+#
+# localhost is used to configure the loopback interface
+# when the system is booting.  Do not change this entry.
+##
+127.0.0.1	localhost
+255.255.255.255	broadcasthost
+::1             localhost
+fe80::1%lo0	localhost
+0.0.0.0	example.com
+127.0.0.1	example.net"
+  _compare "'${_expected}'" "'$(cat "${HOSTS_PATH}")'"
+  [[ "$(cat "${HOSTS_PATH}")" != "${_original}" ]]
+  [[ "$(cat "${HOSTS_PATH}")" == "${_expected}" ]]
+}
+
+@test "\`unblock <hostname>\` prints feedback." {
+  {
+    run "${_HOSTS}" add 0.0.0.0 example.com
+    run "${_HOSTS}" block example.com
+    run "${_HOSTS}" add 127.0.0.1 example.net
+  }
+
+  run "${_HOSTS}" unblock example.com
+  printf "\${status}: %s\n" "${status}"
+  printf "\${output}: '%s'\n" "${output}"
+  _expected="\
+Removed:
+127.0.0.1	example.com
+Removed:
+fe80::1%lo0	example.com
+Removed:
+::1	example.com"
+  [[ "${output}" == "${_expected}" ]]
+}
+
+# help ########################################################################
+
+@test "\`help unblock\` exits with status 0." {
+  run "${_HOSTS}" help unblock
+  [[ ${status} -eq 0 ]]
+}
+
+@test "\`help unblock\` prints help information." {
+  run "${_HOSTS}" help unblock
+  printf "\${status}: %s\n" "${status}"
+  printf "\${output}: '%s'\n" "${output}"
+  [[ "${lines[0]}" == "Usage:" ]]
+  [[ "${lines[1]}" == "  hosts unblock <hostname>" ]]
+}