diff --git a/clean_files.txt b/clean_files.txt
index 54180c19fd..6273bccc7b 100644
--- a/clean_files.txt
+++ b/clean_files.txt
@@ -33,50 +33,80 @@ lint_clean_files.sh
 #
 completion/available/apm.completion.bash
 completion/available/awless.completion.bash
+completion/available/awscli.completion.bash
 completion/available/bash-it.completion.bash
 completion/available/brew.completion.bash
+#completion/available/capistrano.completion.bash
 completion/available/cargo.completion.bash
 completion/available/composer.completion.bash
 completion/available/conda.completion.bash
 completion/available/consul.completion.bash
+completion/available/crystal.completion.bash
 completion/available/dart.completion.bash
+completion/available/defaults.completion.bash
+completion/available/dirs.completion.bash
 completion/available/django.completion.bash
 completion/available/dmidecode.completion.bash
 completion/available/docker-machine.completion.bash
 completion/available/docker.completion.bash
 completion/available/dotnet.completion.bash
+completion/available/drush.completion.bash
+completion/available/export.completion.bash
+completion/available/flutter.completion.bash
 completion/available/gcloud.completion.bash
 completion/available/gem.completion.bash
 completion/available/git.completion.bash
 completion/available/github-cli.completion.bash
 completion/available/go.completion.bash
 completion/available/helm.completion.bash
+completion/available/homesick.completion.bash
 completion/available/jboss5.completion.bash
 completion/available/jboss7.completion.bash
 completion/available/jungle.completion.bash
+completion/available/kind.completion.bash
 completion/available/knife.completion.bash
 completion/available/kontena.completion.bash
 completion/available/kubectl.completion.bash
 completion/available/laravel.completion.bash
 completion/available/lerna.completion.bash
+completion/available/makefile.completion.bash
+#completion/available/maven.completion.bash
 completion/available/minikube.completion.bash
+completion/available/minishift.completion.bash
+completion/available/ng.completion.bash
 completion/available/ngrok.completion.bash
 completion/available/notify-send.completion.bash
 completion/available/npm.completion.bash
+completion/available/nvm.completion.bash
+completion/available/openshift.completion.bash
 completion/available/packer.completion.bash
+completion/available/pew.completion.bash
 completion/available/pip.completion.bash
 completion/available/pip3.completion.bash
 completion/available/pipenv.completion.bash
 completion/available/pipx.completion.bash
+#completion/available/projects.completion.bash
+#completion/available/rake.completion.bash
 completion/available/rustup.completion.bash
+completion/available/rvm.completion.bash
 completion/available/sdkman.completion.bash
+#completion/available/sqlmap.completion.bash
+#completion/available/ssh.completion.bash
+completion/available/svn.completion.bash
 completion/available/system.completion.bash
+completion/available/terraform.completion.bash
+#completion/available/test_kitchen.completion.bash
+completion/available/todo.completion.bash
+completion/available/travis.completion.bash
 completion/available/vault.completion.bash
+completion/available/virsh.completion.bash
+#completion/available/virtualbox.completion.bash
 completion/available/vuejs.completion.bash
 completion/available/wpscan.completion.bash
 
 # libraries
 lib/colors.bash
+lib/completion.bash
 lib/helpers.bash
 lib/history.bash
 lib/log.bash
diff --git a/completion/available/apm.completion.bash b/completion/available/apm.completion.bash
index c3dcfe45f8..9737938f24 100644
--- a/completion/available/apm.completion.bash
+++ b/completion/available/apm.completion.bash
@@ -1,4 +1,4 @@
 # shellcheck shell=bash
 about-completion "apm completion"
-# shellcheck disable=SC1090
-source "${BASH_IT}"/vendor/github.com/vigo/apm-bash-completion/apm
+# shellcheck source-path=SCRIPTDIR/../../vendor/github.com/vigo/apm-bash-completion
+source "${BASH_IT?}/vendor/github.com/vigo/apm-bash-completion/apm"
diff --git a/completion/available/awless.completion.bash b/completion/available/awless.completion.bash
index 98a5d38881..9d175e7502 100644
--- a/completion/available/awless.completion.bash
+++ b/completion/available/awless.completion.bash
@@ -1,5 +1,10 @@
 # shellcheck shell=bash
-if _command_exists awless; then
-	# shellcheck disable=SC1090
-	source <(awless completion bash)
-fi
+
+# Make sure awless is installed
+_bash-it-completion-helper-necessary awless || return
+
+# Don't handle completion if it's already managed
+_bash-it-completion-helper-sufficient awless || return
+
+# shellcheck disable=SC1090
+source <(awless completion bash)
diff --git a/completion/available/awscli.completion.bash b/completion/available/awscli.completion.bash
index a30418373a..bb5bd6b0d5 100644
--- a/completion/available/awscli.completion.bash
+++ b/completion/available/awscli.completion.bash
@@ -1,6 +1,9 @@
 # shellcheck shell=bash
 
-if _command_exists aws_completer
-then
-	complete -C "$(command -v aws_completer)" aws
-fi
+# Make sure aws is installed
+_bash-it-completion-helper-necessary aws aws_completer || return
+
+# Don't handle completion if it's already managed
+_bash-it-completion-helper-sufficient aws || return
+
+complete -C aws_completer aws
diff --git a/completion/available/cargo.completion.bash b/completion/available/cargo.completion.bash
index d276ee7298..d40d4d4948 100644
--- a/completion/available/cargo.completion.bash
+++ b/completion/available/cargo.completion.bash
@@ -1,6 +1,10 @@
 # shellcheck shell=bash
-# cargo (Rust package manager) completion
+about-completion "cargo (Rust package manager) completion"
 
-if _binary_exists rustup && _binary_exists cargo; then
-	eval "$(rustup completions bash cargo)"
-fi
+# Make sure cargo is installed
+_bash-it-completion-helper-necessary rustup cargo || return
+
+# Don't handle completion if it's already managed
+_bash-it-completion-helper-sufficient cargo || return
+
+eval "$(rustup completions bash cargo)"
diff --git a/completion/available/conda.completion.bash b/completion/available/conda.completion.bash
index f5a61e5907..84399caec3 100644
--- a/completion/available/conda.completion.bash
+++ b/completion/available/conda.completion.bash
@@ -1,5 +1,4 @@
 # shellcheck shell=bash
-cite "about-completion"
 about-completion "conda completion"
 
 if _command_exists conda; then
diff --git a/completion/available/consul.completion.bash b/completion/available/consul.completion.bash
index 511cf37209..2fbc6c6941 100644
--- a/completion/available/consul.completion.bash
+++ b/completion/available/consul.completion.bash
@@ -1,7 +1,10 @@
 # shellcheck shell=bash
-cite "about-completion"
 about-completion "Hashicorp consul completion"
 
-if _command_exists consul; then
-	complete -C "$(command -v consul)" consul
-fi
+# Make sure consul is installed
+_bash-it-completion-helper-necessary consul || return
+
+# Don't handle completion if it's already managed
+_bash-it-completion-helper-sufficient consul || return
+
+complete -C consul consul
diff --git a/completion/available/crystal.completion.bash b/completion/available/crystal.completion.bash
index 7644ffd4d4..950459aa71 100644
--- a/completion/available/crystal.completion.bash
+++ b/completion/available/crystal.completion.bash
@@ -1 +1,4 @@
-_log_warning 'Bash completion for "crystal" is now covered by "system". This completion can be disabled.'
+# shellcheck shell=bash
+
+_log_warning 'Bash completion for "crystal" is now covered by "system".'
+_disable-completion "crystal"
diff --git a/completion/available/defaults.completion.bash b/completion/available/defaults.completion.bash
index 39d7ea95b0..9fb00da619 100644
--- a/completion/available/defaults.completion.bash
+++ b/completion/available/defaults.completion.bash
@@ -1,5 +1,6 @@
 # shellcheck shell=bash
 
-if test -s "${BASH_IT?}/vendor/github.com/gaelicWizard/bash-progcomp/defaults.completion.bash"; then
-	source "$_"
+if [[ -s "${BASH_IT?}/vendor/github.com/gaelicWizard/bash-progcomp/defaults.completion.bash" ]]; then
+	# shellcheck source-path=SCRIPTDIR/../../vendor/github.com/gaelicWizard/bash-progcomp
+	source "${BASH_IT?}/vendor/github.com/gaelicWizard/bash-progcomp/defaults.completion.bash"
 fi
diff --git a/completion/available/dirs.completion.bash b/completion/available/dirs.completion.bash
index ba18db3241..187de36119 100644
--- a/completion/available/dirs.completion.bash
+++ b/completion/available/dirs.completion.bash
@@ -1,15 +1,13 @@
-#!/usr/bin/env bash
-# Bash completion support for the 'dirs' plugin (commands G, R).
+# shellcheck shell=bash
+about-completion "Bash completion support for the 'dirs' plugin (commands G, R)."
 
-_dirs-complete() {
-    local CURRENT_PROMPT="${COMP_WORDS[COMP_CWORD]}"
+function _dirs-complete() {
+	# parse all defined shortcuts ${BASH_IT_DIRS_BKS}
+	if [[ -s "${BASH_IT_DIRS_BKS:-/dev/null}" ]]; then
+		IFS=$'\n' read -d '' -ra COMPREPLY < <(grep -v '^#' "${BASH_IT_DIRS_BKS?}" | sed -e 's/\(.*\)=.*/\1/')
+	fi
 
-    # parse all defined shortcuts from ~/.dirs
-    if [ -r "$HOME/.dirs" ]; then
-        COMPREPLY=($(compgen -W "$(grep -v '^#' ~/.dirs | sed -e 's/\(.*\)=.*/\1/')" -- ${CURRENT_PROMPT}) )
-    fi
-
-    return 0
+	return 0
 }
 
-complete -o default -o nospace -F _dirs-complete G R
+complete -o default -o nospace -F _dirs-complete -X '!&*' G R
diff --git a/completion/available/dmidecode.completion.bash b/completion/available/dmidecode.completion.bash
index 4a8845244e..eacfee81fe 100644
--- a/completion/available/dmidecode.completion.bash
+++ b/completion/available/dmidecode.completion.bash
@@ -1,22 +1,25 @@
 # shellcheck shell=bash
 
-function __dmidecode_completion() {
-	# shellcheck disable=SC2155
-	local prev=$(_get_pword)
-	# shellcheck disable=SC2155
-	local curr=$(_get_cword)
+# Make sure dmidecode is installed
+_bash-it-completion-helper-necessary dmidecode || :
+
+# Don't handle completion if it's already managed
+_bash-it-completion-helper-sufficient dmidecode || return
+
+function _dmidecode() {
+	local prev="${COMP_WORDS[COMP_CWORD - 1]}"
 
 	case $prev in
 		-s | --string | -t | --type)
 			OPTS=$(dmidecode "$prev" 2>&1 | grep -E '^ ' | sed 's/ *//g')
 			# shellcheck disable=SC2207
-			COMPREPLY=($(compgen -W "$OPTS" -- "$curr"))
+			COMPREPLY=("${OPTS[@]}")
 			;;
 		dmidecode)
 			# shellcheck disable=SC2207
-			COMPREPLY=($(compgen -W "-d --dev-mem -h --help -q --quiet -s --string -t --type -H --handle -u --dump{,-bin} --from-dump --no-sysfs --oem-string -V --version" -- "$curr"))
+			COMPREPLY=("-d" "--dev-mem" "-h" "--help" "-q" "--quiet" "-s" "--string" "-t" "--type" "-H" "--handle" "-u" "--dump" "-dump-bin" "--from-dump" "--no-sysfs" "--oem-string" "-V" "--version")
 			;;
 	esac
 }
 
-complete -F __dmidecode_completion dmidecode
+complete -F _dmidecode -X '!&*' dmidecode
diff --git a/completion/available/docker.completion.bash b/completion/available/docker.completion.bash
index 3f83a87461..b23be80e4b 100644
--- a/completion/available/docker.completion.bash
+++ b/completion/available/docker.completion.bash
@@ -1,24 +1,32 @@
 # shellcheck shell=bash
-cite "about-completion"
 about-completion "docker completion"
 
 # Make sure docker is installed
-_command_exists docker || return
+_bash-it-completion-helper-necessary docker || :
 
 # Don't handle completion if it's already managed
-_completion_exists docker && return
+_bash-it-completion-helper-sufficient docker || return
 
 _docker_bash_completion_paths=(
-	# MacOS
+	# MacOS App
 	'/Applications/Docker.app/Contents/Resources/etc/docker.bash-completion'
-	# Linux
+	# Command Line
 	'/usr/share/bash-completion/completions/docker'
 )
 
-for fn in "${_docker_bash_completion_paths[@]}"; do
-	if [ -r "$fn" ]; then
+# Load the first completion file found
+_docker_bash_completion_found=false
+for _comp_path in "${_docker_bash_completion_paths[@]}"; do
+	if [[ -r "$_comp_path" ]]; then
+		_docker_bash_completion_found=true
 		# shellcheck disable=SC1090
-		source "$fn"
+		source "$_comp_path"
 		break
 	fi
 done
+
+# Cleanup
+if [[ "${_docker_bash_completion_found}" == false ]]; then
+	_log_warning "no completion files found - please try enabling the 'system' completion instead."
+fi
+unset "${!_docker_bash_completion@}"
diff --git a/completion/available/drush.completion.bash b/completion/available/drush.completion.bash
index 6628c65513..3bc81f1905 100644
--- a/completion/available/drush.completion.bash
+++ b/completion/available/drush.completion.bash
@@ -1,2 +1,5 @@
+# shellcheck shell=bash
+
 _log_warning 'Bash completion for "drush" is now deprecated, as it used code with incompatible license.
 Please disable this completion and use the instructions from "drush" developers instead.'
+_disable-completion "drush"
diff --git a/completion/available/export.completion.bash b/completion/available/export.completion.bash
index 42da3a97be..361ead75b6 100644
--- a/completion/available/export.completion.bash
+++ b/completion/available/export.completion.bash
@@ -1 +1,4 @@
-complete -o nospace -S = -W '$(printenv | awk -F= "{print \$1}")' export
+# shellcheck shell=bash
+
+_log_warning 'Bash completion for "export" is now covered by "system".'
+_disable-completion "export"
diff --git a/completion/available/flutter.completion.bash b/completion/available/flutter.completion.bash
index 62befc824d..cc965b579e 100644
--- a/completion/available/flutter.completion.bash
+++ b/completion/available/flutter.completion.bash
@@ -1,5 +1,9 @@
-#!/usr/bin/bash
+# shellcheck shell=bash
 
-if _command_exists flutter; then
-  eval "$(flutter bash-completion)"
-fi
+# Make sure flutter is installed
+_bash-it-completion-helper-necessary flutter || return
+
+# Don't handle completion if it's already managed
+_bash-it-completion-helper-sufficient flutter || return
+
+eval "$(flutter bash-completion)"
diff --git a/completion/available/gcloud.completion.bash b/completion/available/gcloud.completion.bash
index 63073e8ed3..514d8b4c3d 100644
--- a/completion/available/gcloud.completion.bash
+++ b/completion/available/gcloud.completion.bash
@@ -1,5 +1,4 @@
 # shellcheck shell=bash
-cite "about-completion"
 about-completion "Google Cloud SDK completion"
 
 if _command_exists gcloud; then
diff --git a/completion/available/git.completion.bash b/completion/available/git.completion.bash
index 31b77fa3de..d9fe014c91 100644
--- a/completion/available/git.completion.bash
+++ b/completion/available/git.completion.bash
@@ -3,13 +3,10 @@
 # Locate and load completions for `git`.
 
 # Make sure git is installed
-_command_exists git || return
+_bash-it-completion-helper-necessary git || :
 
 # Don't handle completion if it's already managed
-if complete -p git &> /dev/null; then
-	_log_warning "completion already loaded - this usually means it is safe to stop using this completion"
-	return 0
-fi
+_bash-it-completion-helper-sufficient git || return
 
 _git_bash_completion_xcrun_git=
 if _command_exists xcrun; then
diff --git a/completion/available/github-cli.completion.bash b/completion/available/github-cli.completion.bash
index 4a6113945c..0888c6c5eb 100644
--- a/completion/available/github-cli.completion.bash
+++ b/completion/available/github-cli.completion.bash
@@ -1,9 +1,10 @@
 # shellcheck shell=bash
-cite "about-completion"
 about-completion "GitHub CLI completion"
 
-if _binary_exists gh; then
-	# If gh already completed, stop
-	_completion_exists gh && return
-	eval "$(gh completion --shell=bash)"
-fi
+# Make sure gh is installed
+_bash-it-completion-helper-necessary gh || return
+
+# Don't handle completion if it's already managed
+_bash-it-completion-helper-sufficient gh || return
+
+eval "$(gh completion --shell=bash)"
diff --git a/completion/available/helm.completion.bash b/completion/available/helm.completion.bash
index 0dae7af46b..d11b4c305b 100644
--- a/completion/available/helm.completion.bash
+++ b/completion/available/helm.completion.bash
@@ -1,7 +1,10 @@
 # shellcheck shell=bash
-cite "about-completion"
 about-completion "helm (Kubernetes Package Manager) completion"
 
-if _command_exists helm; then
-	eval "$(helm completion bash)"
-fi
+# Make sure helm is installed
+_bash-it-completion-helper-necessary helm || return
+
+# Don't handle completion if it's already managed
+_bash-it-completion-helper-sufficient helm || return
+
+eval "$(helm completion bash)"
diff --git a/completion/available/homesick.completion.bash b/completion/available/homesick.completion.bash
index ed6f6e79ed..cd2e00b0a8 100644
--- a/completion/available/homesick.completion.bash
+++ b/completion/available/homesick.completion.bash
@@ -1,2 +1,5 @@
+# shellcheck shell=bash
+
 _log_warning 'Bash completion for "homesick" is now deprecated, as it used unlicensed code.
 Please disable this completion and use the instructions from "homesick" bash completion developers instead.'
+_disable-completion "homesick"
diff --git a/completion/available/jungle.completion.bash b/completion/available/jungle.completion.bash
index e190d1438a..60aa398920 100644
--- a/completion/available/jungle.completion.bash
+++ b/completion/available/jungle.completion.bash
@@ -1,7 +1,10 @@
 # shellcheck shell=bash
-cite "about-completion"
 about-completion "jungle(AWS cli tool) completion"
 
-if _command_exists jungle; then
-	eval "$(_JUNGLE_COMPLETE=source jungle)"
-fi
+# Make sure jungle is installed
+_bash-it-completion-helper-necessary jungle || return
+
+# Don't handle completion if it's already managed
+_bash-it-completion-helper-sufficient jungle || return
+
+eval "$(_JUNGLE_COMPLETE=source jungle)"
diff --git a/completion/available/kind.completion.bash b/completion/available/kind.completion.bash
index be12a2d29c..8530dcd454 100644
--- a/completion/available/kind.completion.bash
+++ b/completion/available/kind.completion.bash
@@ -1,5 +1,9 @@
-#!/usr/bin/env bash
+# shellcheck shell=bash
 
-if _command_exists kind; then
-  eval "$(kind completion bash)"
-fi
+# Make sure kind is installed
+_bash-it-completion-helper-necessary kind || return
+
+# Don't handle completion if it's already managed
+_bash-it-completion-helper-sufficient kind || return
+
+eval "$(kind completion bash)"
diff --git a/completion/available/kontena.completion.bash b/completion/available/kontena.completion.bash
index 916ee15f92..08f6ef634b 100644
--- a/completion/available/kontena.completion.bash
+++ b/completion/available/kontena.completion.bash
@@ -1,5 +1,10 @@
 # shellcheck shell=bash
-if _command_exists kontena; then
-	# shellcheck disable=SC1090
-	source "$(kontena whoami --bash-completion-path)"
-fi
+
+# Make sure kontena is installed
+_bash-it-completion-helper-necessary kontena || return
+
+# Don't handle completion if it's already managed
+_bash-it-completion-helper-sufficient kontena || return
+
+# shellcheck disable=SC1090
+source "$(kontena whoami --bash-completion-path)"
diff --git a/completion/available/kubectl.completion.bash b/completion/available/kubectl.completion.bash
index a9c498b601..f3d9ec5a94 100644
--- a/completion/available/kubectl.completion.bash
+++ b/completion/available/kubectl.completion.bash
@@ -1,7 +1,10 @@
 # shellcheck shell=bash
-cite "about-completion"
 about-completion "kubectl (Kubernetes CLI) completion"
 
-if _binary_exists kubectl; then
-	eval "$(kubectl completion bash)"
-fi
+# Make sure kubectl is installed
+_bash-it-completion-helper-necessary kubectl || return
+
+# Don't handle completion if it's already managed
+_bash-it-completion-helper-sufficient kubectl || return
+
+eval "$(kubectl completion bash)"
diff --git a/completion/available/laravel.completion.bash b/completion/available/laravel.completion.bash
index 8f03256896..63693fe257 100644
--- a/completion/available/laravel.completion.bash
+++ b/completion/available/laravel.completion.bash
@@ -1,6 +1,10 @@
 # shellcheck shell=bash
 
-_command_exists laravel || return
+# Make sure laravel is installed
+_bash-it-completion-helper-necessary laravel || :
+
+# Don't handle completion if it's already managed
+_bash-it-completion-helper-sufficient laravel || return
 
 function __laravel_completion() {
 	local OPTS=('-h' '--help' '-q' '--quiet' '--ansi' '--no-ansi' '-n' '--no-interaction' '-v' '-vv' '-vvv' '--verbose' 'help' 'list' 'new')
diff --git a/completion/available/makefile.completion.bash b/completion/available/makefile.completion.bash
index e72ba6fd3b..b518bb5793 100644
--- a/completion/available/makefile.completion.bash
+++ b/completion/available/makefile.completion.bash
@@ -1,33 +1,35 @@
+# shellcheck shell=bash
+
 # Bash completion for Makefile
 # Loosely adapted from http://stackoverflow.com/a/38415982/1472048
 
-_makecomplete() {
-  COMPREPLY=()
+function _makecomplete() {
+	local cur="${COMP_WORDS[COMP_CWORD]}"
+	local files=() targets=() line f
+	COMPREPLY=()
 
-  # https://www.gnu.org/software/make/manual/html_node/Makefile-Names.html
-  local files=()
-  for f in 'GNUmakefile' 'makefile' 'Makefile' ; do
-    [ -f "$f" ] && files+=("$f")
-  done
+	# https://www.gnu.org/software/make/manual/html_node/Makefile-Names.html
+	for f in 'GNUmakefile' 'makefile' 'Makefile'; do
+		[[ -f "$f" ]] && files+=("$f")
+	done
 
-  [ "${#files[@]}" -eq 0 ] && return 0
+	[[ "${#files[@]}" -eq 0 ]] && return 0
 
-  # collect all targets
-  local targets=()
-  for f in "${files[@]}" ; do
-    while IFS='' read -r line ; do
-      targets+=("$line")
-    done < <(grep -oE '^[a-zA-Z0-9_-]+:([^=]|$)' "$f" | cut -d':' -f1)
-  done
+	# collect all targets
+	for f in "${files[@]}"; do
+		while IFS='' read -r line; do
+			targets+=("$line")
+		done < <(grep -oE '^[a-zA-Z0-9_-]+:([^=]|$)' "$f" | cut -d':' -f1)
+	done
 
-  [ "${#targets[@]}" -eq 0 ] && return 0
+	[[ "${#targets[@]}" -eq 0 ]] && return 0
 
-  # use the targets for completion
-  while IFS='' read -r line ; do
-    COMPREPLY+=("$line")
-  done < <(compgen -W "$(tr ' ' '\n' <<<"${targets[@]}" | sort -u)" -- "${COMP_WORDS[COMP_CWORD]}")
+	# use the targets for completion
+	while IFS='' read -r line; do
+		COMPREPLY+=("$line")
+	done < <(compgen -W "$(tr ' ' '\n' <<< "${targets[@]}" | sort -u)" -- "${cur}")
 
-  return 0
+	return 0
 }
 
 complete -o nospace -F _makecomplete make
diff --git a/completion/available/minikube.completion.bash b/completion/available/minikube.completion.bash
index 44076362ce..c73a4da44f 100644
--- a/completion/available/minikube.completion.bash
+++ b/completion/available/minikube.completion.bash
@@ -1,6 +1,10 @@
 # shellcheck shell=bash
-# minikube (Local Kubernetes) completion
+about-completion "minikube (Local Kubernetes) completion"
 
-if _command_exists minikube; then
-	eval "$(minikube completion bash)"
-fi
+# Make sure minikube is installed
+_bash-it-completion-helper-necessary minikube || return
+
+# Don't handle completion if it's already managed
+_bash-it-completion-helper-sufficient minikube || return
+
+eval "$(minikube completion bash)"
diff --git a/completion/available/minishift.completion.bash b/completion/available/minishift.completion.bash
index 5679eae80f..dc872bc1bd 100644
--- a/completion/available/minishift.completion.bash
+++ b/completion/available/minishift.completion.bash
@@ -1 +1,10 @@
-_command_exists minishift && source <(minishift completion bash)
+# shellcheck shell=bash
+
+# Make sure minishift is installed
+_bash-it-completion-helper-necessary minishift || return
+
+# Don't handle completion if it's already managed
+_bash-it-completion-helper-sufficient minishift || return
+
+# shellcheck disable=SC1090
+source <(minishift completion bash)
diff --git a/completion/available/ng.completion.bash b/completion/available/ng.completion.bash
index f219b30396..cba49c3b31 100644
--- a/completion/available/ng.completion.bash
+++ b/completion/available/ng.completion.bash
@@ -1,8 +1,15 @@
-if _command_exists ng; then
-  # No longer supported, please see https://github.com/angular/angular-cli/issues/11043
-  # Fix courtesy of https://stackoverflow.com/questions/50194674/ng-completion-no-longer-exists
-  # . <(ng completion --bash)
-
-  NG_COMMANDS="add build config doc e2e generate help lint new run serve test update version xi18n"
-  complete -W "$NG_COMMANDS" ng
-fi
+# shellcheck shell=bash
+
+# Make sure ng is installed
+_bash-it-completion-helper-necessary ng || :
+
+# Don't handle completion if it's already managed
+_bash-it-completion-helper-sufficient ng || return
+
+# No longer supported, please see https://github.com/angular/angular-cli/issues/11043
+# Fix courtesy of https://stackoverflow.com/questions/50194674/ng-completion-no-longer-exists
+# source <(ng completion --bash)
+
+_ng_bash_completion_candidates=("add" "build" "config" "doc" "e2e" "generate" "help" "lint" "new" "run" "serve" "test" "update" "version" "xi18n")
+complete -W "${_ng_bash_completion_candidates[*]}" ng
+unset "${!_ng_bash_completion@}"
diff --git a/completion/available/notify-send.completion.bash b/completion/available/notify-send.completion.bash
index 676485f83a..4745b2abee 100644
--- a/completion/available/notify-send.completion.bash
+++ b/completion/available/notify-send.completion.bash
@@ -1,21 +1,22 @@
 # shellcheck shell=bash
 
-function __notify-send_completions() {
-	# shellcheck disable=SC2155
-	local curr=$(_get_cword)
-	# shellcheck disable=SC2155
-	local prev=$(_get_pword)
+# Make sure notify-send is installed
+_bash-it-completion-helper-necessary notify-send || :
+
+# Don't handle completion if it's already managed
+_bash-it-completion-helper-sufficient notify-send || return
+
+function _notify-send() {
+	local prev="${COMP_WORDS[COMP_CWORD - 1]}"
 
 	case $prev in
 		-u | --urgency)
-			# shellcheck disable=SC2207
-			COMPREPLY=($(compgen -W "low normal critical" -- "$curr"))
+			COMPREPLY=("low" "normal" "critical")
 			;;
 		*)
-			# shellcheck disable=SC2207
-			COMPREPLY=($(compgen -W "-? --help -u --urgency -t --expire-time -a --app-name -i --icon -c --category -h --hint -v --version" -- "$curr"))
+			COMPREPLY=("-?" "--help" "-u" "--urgency" "-t" "--expire-time" "-a" "--app-name" "-i" "--icon" "-c" "--category" "-h" "--hint" "-v" "--version")
 			;;
 	esac
 }
 
-complete -F __notify-send_completions notify-send
+complete -F _notify-send -X '!&*' notify-send
diff --git a/completion/available/npm.completion.bash b/completion/available/npm.completion.bash
index cf24585ef7..3ceb620252 100644
--- a/completion/available/npm.completion.bash
+++ b/completion/available/npm.completion.bash
@@ -1,7 +1,10 @@
 # shellcheck shell=bash
-cite "about-completion"
 about-completion "npm (Node Package Manager) completion"
 
-if _command_exists npm; then
-	eval "$(npm completion)"
-fi
+# Make sure npm is installed
+_bash-it-completion-helper-necessary npm || return
+
+# Don't handle completion if it's already managed
+_bash-it-completion-helper-sufficient npm || return
+
+eval "$(npm completion)"
diff --git a/completion/available/nvm.completion.bash b/completion/available/nvm.completion.bash
index a82b82b61a..9126f4d68b 100644
--- a/completion/available/nvm.completion.bash
+++ b/completion/available/nvm.completion.bash
@@ -1,8 +1,7 @@
-#!/usr/bin/env bash
+# shellcheck shell=bash
+about-completion "nvm (Node Version Manager) completion"
 
-# nvm (Node Version Manager) completion
-
-if [ "$NVM_DIR" ] && [ -r "$NVM_DIR"/bash_completion ];
-then
-  . "$NVM_DIR"/bash_completion
+if [[ -n "${NVM_DIR:-}" && -s "${NVM_DIR}/bash_completion" ]]; then
+	# shellcheck disable=SC1091
+	source "${NVM_DIR}/bash_completion"
 fi
diff --git a/completion/available/openshift.completion.bash b/completion/available/openshift.completion.bash
index 1e7b681506..5d0e2dcdc3 100644
--- a/completion/available/openshift.completion.bash
+++ b/completion/available/openshift.completion.bash
@@ -1 +1,10 @@
-_command_exists oc && source <(oc completion bash)
+# shellcheck shell=bash
+
+# Make sure oc is installed
+_bash-it-completion-helper-necessary oc || return
+
+# Don't handle completion if it's already managed
+_bash-it-completion-helper-sufficient oc || return
+
+# shellcheck disable=SC1090
+source <(oc completion bash)
diff --git a/completion/available/packer.completion.bash b/completion/available/packer.completion.bash
index 2301f0f226..049e17ae34 100644
--- a/completion/available/packer.completion.bash
+++ b/completion/available/packer.completion.bash
@@ -1,7 +1,10 @@
 # shellcheck shell=bash
-cite "about-completion"
 about-completion "packer completion"
 
-if _binary_exists packer; then
-	complete -C packer packer
-fi
+# Make sure packer is installed
+_bash-it-completion-helper-necessary packer || return
+
+# Don't handle completion if it's already managed
+_bash-it-completion-helper-sufficient packer || return
+
+complete -C packer packer
diff --git a/completion/available/pew.completion.bash b/completion/available/pew.completion.bash
index 04e67ecbf5..221df24958 100644
--- a/completion/available/pew.completion.bash
+++ b/completion/available/pew.completion.bash
@@ -1,6 +1,10 @@
 # shellcheck shell=bash
 
-if _command_exists pew
-then
-	source "$(pew shell_config)"
-fi
+# Make sure pew is installed
+_bash-it-completion-helper-necessary pew || return
+
+# Don't handle completion if it's already managed
+_bash-it-completion-helper-sufficient pew || return
+
+# shellcheck disable=SC1090
+source "$(pew shell_config)"
diff --git a/completion/available/pipenv.completion.bash b/completion/available/pipenv.completion.bash
index 4adfab9595..43cbe74e17 100644
--- a/completion/available/pipenv.completion.bash
+++ b/completion/available/pipenv.completion.bash
@@ -1,4 +1,9 @@
 # shellcheck shell=bash
-if _command_exists pipenv; then
-	eval "$(_PIPENV_COMPLETE=bash_source pipenv)"
-fi
+
+# Make sure pipenv is installed
+_bash-it-completion-helper-necessary pipenv || return
+
+# Don't handle completion if it's already managed
+_bash-it-completion-helper-sufficient pipenv || return
+
+eval "$(_PIPENV_COMPLETE=bash_source pipenv)"
diff --git a/completion/available/rustup.completion.bash b/completion/available/rustup.completion.bash
index 1cf8bc95b4..1f1a38af2f 100644
--- a/completion/available/rustup.completion.bash
+++ b/completion/available/rustup.completion.bash
@@ -1,7 +1,10 @@
 # shellcheck shell=bash
+about-completion "rustup (Rust toolchain installer) completion"
 
-# rustup (Rust toolchain installer) completion
+# Make sure rustup is installed
+_bash-it-completion-helper-necessary rustup || return
 
-if _binary_exists rustup; then
-	eval "$(rustup completions bash)"
-fi
+# Don't handle completion if it's already managed
+_bash-it-completion-helper-sufficient rustup || return
+
+eval "$(rustup completions bash)"
diff --git a/completion/available/rvm.completion.bash b/completion/available/rvm.completion.bash
index cd8ded0468..9bea6ebb67 100644
--- a/completion/available/rvm.completion.bash
+++ b/completion/available/rvm.completion.bash
@@ -1,5 +1,8 @@
-#!/usr/bin/env bash
-# Bash completion support for  RVM.
+# shellcheck shell=bash
+about-completion "Bash completion support for  RVM."
 # Source: https://rvm.io/workflow/completion
 
-[[ -r $rvm_path/scripts/completion ]] && . $rvm_path/scripts/completion
+if [[ -n "${rvm_path:-}" && -s "${rvm_path}/scripts/completion" ]]; then
+	# shellcheck disable=SC1091
+	source "${rvm_path}/scripts/completion"
+fi
diff --git a/completion/available/svn.completion.bash b/completion/available/svn.completion.bash
index 2f0a23fe97..8d24066caa 100644
--- a/completion/available/svn.completion.bash
+++ b/completion/available/svn.completion.bash
@@ -3,13 +3,10 @@
 # Locate and load completions for `svn`.
 
 # Make sure svn is installed
-_command_exists svn || return
+_bash-it-completion-helper-necessary svn || :
 
 # Don't handle completion if it's already managed
-if _completion_exists svn; then
-	_log_warning "completion already loaded - this usually means it is safe to stop using this completion"
-	return 0
-fi
+_bash-it-completion-helper-sufficient svn || return
 
 _svn_bash_completion_xcrun_svn=
 if _command_exists xcrun; then
diff --git a/completion/available/terraform.completion.bash b/completion/available/terraform.completion.bash
index 1452fca8b2..8175769bdc 100644
--- a/completion/available/terraform.completion.bash
+++ b/completion/available/terraform.completion.bash
@@ -1,10 +1,10 @@
-#!/usr/bin/env bash
+# shellcheck shell=bash
 
 # Make sure terraform is installed
-_command_exists terraform || return
+_bash-it-completion-helper-necessary terraform || return
 
 # Don't handle completion if it's already managed
-complete -p terraform &>/dev/null && return
+_bash-it-completion-helper-sufficient terraform || return
 
 # Terraform completes itself
 complete -C terraform terraform
diff --git a/completion/available/todo.completion.bash b/completion/available/todo.completion.bash
index b5517d8654..ed2a48ab9c 100644
--- a/completion/available/todo.completion.bash
+++ b/completion/available/todo.completion.bash
@@ -1,2 +1,5 @@
+# shellcheck shell=bash
+
 _log_warning 'Bash completion for "todo.txt-cli" is now deprecated, as it used code with incompatible license.
 Please disable this completion and use the instructions from "todo.txt-cli" developers instead.'
+_disable-completion "todo"
diff --git a/completion/available/travis.completion.bash b/completion/available/travis.completion.bash
index 49d8f2cc92..0a1d0088f4 100644
--- a/completion/available/travis.completion.bash
+++ b/completion/available/travis.completion.bash
@@ -1,10 +1,13 @@
 # shellcheck shell=bash
 
-if _command_exists travis
-then
-  if [[ -s "${__TRAVIS_COMPLETION_SCRIPT:=${TRAVIS_CONFIG_PATH:-${HOME}/.travis}/travis.sh}" ]]
-	then
-		source "${__TRAVIS_COMPLETION_SCRIPT}"
-	fi
-  unset __TRAVIS_COMPLETION_SCRIPT
+# Make sure travis is installed
+_bash-it-completion-helper-necessary travis || :
+
+# Don't handle completion if it's already managed
+_bash-it-completion-helper-sufficient travis || return
+
+if [[ -s "${_travis_bash_completion_script:=${TRAVIS_CONFIG_PATH:-${HOME}/.travis}/travis.sh}" ]]; then
+	# shellcheck disable=SC1090
+	source "${_travis_bash_completion_script}"
 fi
+unset "${!_travis_bash_completion@}"
diff --git a/completion/available/vault.completion.bash b/completion/available/vault.completion.bash
index 9520f166b1..6ce9d736ac 100644
--- a/completion/available/vault.completion.bash
+++ b/completion/available/vault.completion.bash
@@ -1,7 +1,10 @@
 # shellcheck shell=bash
-cite "about-completion"
 about-completion "vault completion"
 
-if _binary_exists vault; then
-	complete -C vault vault
-fi
+# Make sure vault is installed
+_bash-it-completion-helper-necessary vault || return
+
+# Don't handle completion if it's already managed
+_bash-it-completion-helper-sufficient vault || return
+
+complete -C vault vault
diff --git a/completion/available/virsh.completion.bash b/completion/available/virsh.completion.bash
index 6450b4a305..74967e5d59 100644
--- a/completion/available/virsh.completion.bash
+++ b/completion/available/virsh.completion.bash
@@ -1,2 +1,5 @@
+# shellcheck shell=bash
+
 _log_warning 'Bash completion for "virsh" is now deprecated, as it used code with incompatible license.
 Please disable this completion and use the instructions from "virsh" developers instead.'
+_disable-completion "virsh"
diff --git a/completion/available/vuejs.completion.bash b/completion/available/vuejs.completion.bash
index 751658f0c9..b7ee31980e 100644
--- a/completion/available/vuejs.completion.bash
+++ b/completion/available/vuejs.completion.bash
@@ -1,61 +1,61 @@
 # shellcheck shell=bash
 
-__vuejs_completion() {
-	# shellcheck disable=SC2155
-	local prev=$(_get_pword)
-	# shellcheck disable=SC2155
-	local curr=$(_get_cword)
+# Make sure vue is installed
+_bash-it-completion-helper-necessary vue || :
+
+# Don't handle completion if it's already managed
+_bash-it-completion-helper-sufficient vue || return
+
+function _vuejs() {
+	local prev="${COMP_WORDS[COMP_CWORD - 1]}"
 
 	case $prev in
 		create)
-			# shellcheck disable=SC2207
-			COMPREPLY=($(compgen -W "-p -d -i -m -r -g -n -f -c -x -b -h --help --preset --default --inilinePreset --packageManager --registry --git --no-git --force --merge --clone --proxy --bare  --skipGetStarted" -- "$curr"))
+			COMPREPLY=("-p" "-d" "-i" "-m" "-r" "-g" "-n" "-f" "-c" "-x" "-b"
+				"-h" "--help" "--preset" "--default" "--inilinePreset"
+				"--packageManager" "--registry" "--git" "--no-git" "--force"
+				"--merge" "--clone" "--proxy" "--bare" "" "--skipGetStarted")
 			;;
 		add | invoke)
-			# shellcheck disable=SC2207
-			COMPREPLY=($(compgen -W "--registry -h --help" -- "$curr"))
+			COMPREPLY=("--registry" "-h" "--help")
 			;;
 		inspect)
-			# shellcheck disable=SC2207
-			COMPREPLY=($(compgen -W "-v --help --verbose --mode --rule --plugin --plugins --rules" -- "$curr"))
+			COMPREPLY=("-v" "--help" "--verbose" "--mode" "--rule" "--plugin"
+				"--plugins" "--rules")
 			;;
 		serve)
-			# shellcheck disable=SC2207
-			COMPREPLY=($(compgen -W "-o -h --help --open -c --copy -p --port" -- "$curr"))
+			COMPREPLY=("-o" "-h" "--help" "--open" "-c" "--copy" "-p" "--port")
 			;;
 		build)
-			# shellcheck disable=SC2207
-			COMPREPLY=($(compgen -W "-t --target -n --name -d --dest -h --help" -- "$curr"))
+			COMPREPLY=("-t" "--target" "-n" "--name" "-d" "--dest" "-h" "--help")
 			;;
 		ui)
-			# shellcheck disable=SC2207
-			COMPREPLY=($(compgen -W "-H --host -p --port -D --dev --quiet --headless -h --help" -- "$curr"))
+			COMPREPLY=("-H" "--host" "-p" "--port" "-D" "--dev" "--quiet"
+				"--headless" "-h" "--help")
 			;;
 		init)
-			# shellcheck disable=SC2207
-			COMPREPLY=($(compgen -W "-c --clone --offline -h --help" -- "$curr"))
+			COMPREPLY=("-c" "--clone" "--offline" "-h" "--help")
 			;;
 		config)
-			# shellcheck disable=SC2207
-			COMPREPLY=($(compgen -W "-g --get -s --set -d --delete -e --edit --json -h --help" -- "$curr"))
+			COMPREPLY=("-g" "--get" "-s" "--set" "-d" "--delete" "-e" "--edit"
+				"--json" "-h" "--help")
 			;;
 		outdated)
-			# shellcheck disable=SC2207
-			COMPREPLY=($(compgen -W "--next -h --help" -- "$curr"))
+			COMPREPLY=("--next" "-h" "--help")
 			;;
 		upgrade)
-			# shellcheck disable=SC2207
-			COMPREPLY=($(compgen -W "-t --to -f --from -r --registry --all --next -h --help" -- "$curr"))
+			COMPREPLY=("-t" "--to" "-f" "--from" "-r" "--registry" "--all"
+				"--next" "-h" "--help")
 			;;
 		migrate)
-			# shellcheck disable=SC2207
-			COMPREPLY=($(compgen -W "-f --from -h --help" -- "$curr"))
+			COMPREPLY=("-f" "--from" "-h" "--help")
 			;;
 		*)
-			# shellcheck disable=SC2207
-			COMPREPLY=($(compgen -W "-h --help -v --version create add invoke inspect serve build ui init config outdated upgrade migrate info" -- "$curr"))
+			COMPREPLY=("-h" "--help" "-v" "--version" "create" "add" "invoke"
+				"inspect" "serve" "build" "ui" "init" "config" "outdated"
+				"upgrade" "migrate" "info")
 			;;
 	esac
 }
 
-complete -F __vuejs_completion vue
+complete -F _vuejs -X '!&*' vue
diff --git a/completion/available/wpscan.completion.bash b/completion/available/wpscan.completion.bash
index 105468a356..9c5a95c13b 100644
--- a/completion/available/wpscan.completion.bash
+++ b/completion/available/wpscan.completion.bash
@@ -1,8 +1,12 @@
 # shellcheck shell=bash
 
-_command_exists wpscan || return
+# Make sure wpscan is installed
+_bash-it-completion-helper-necessary wpscan || :
 
-function __wpscan_completion() {
+# Don't handle completion if it's already managed
+_bash-it-completion-helper-sufficient wpscan || return
+
+function __wpscan() {
 	local _opt_
 	local OPTS=('--help' '--hh' '--version' '--url' '--ignore-main-redirect' '--verbose' '--output' '--format' '--detection-mode' '--scope' '--headers' '--user-agent' '--vhost' '--random-user-agent' '--user-agents-list' '--http-auth' '--max-threads' '--throttle' '--request-timeout' '--connect-timeout' '--disable-tlc-checks' '--proxy' '--proxy-auth' '--cookie-string' '--cookie-jar' '--cache-ttl' '--clear-cache' '--server' '--cache-dir' '--update' '--no-update' '--wp-content-dir' '--wp-plugins-dir' '--wp-version-detection' '--main-theme-detection' '--enumerate' '--exclude-content-based' '--plugins-list' '--plugins-detection' '--plugins-version-all' '--plugins-version-detection' '--themes-list' '--themes-detection' '--themes-version-all' '--themes-version-detection' '--timthumbs-list' '--timthumbs-detection' '--config-backups-list' '--config-backups-detection' '--db-exports-list' '--db-exports-detection' '--medias-detection' '--users-list' '--users-detection' '--passwords' '--usernames' '--multicall-max-passwords' '--password-attack' '--stealthy')
 	COMPREPLY=()
@@ -13,4 +17,4 @@ function __wpscan_completion() {
 	done
 }
 
-complete -F __wpscan_completion wpscan
+complete -F __wpscan wpscan
diff --git a/lib/completion.bash b/lib/completion.bash
new file mode 100644
index 0000000000..fb74f1f94b
--- /dev/null
+++ b/lib/completion.bash
@@ -0,0 +1,49 @@
+# shellcheck shell=bash
+# Functions for working with _Bash_'s Programmable Completion
+
+#
+##
+# Testing Completion Functions
+##
+#
+
+#
+
+#
+##
+# Generating Completion Results
+##
+#
+
+#
+
+#
+##
+# Loading _Bash It_'s Completion Plugins
+##
+
+function _bash-it-completion-helper-necessary() {
+	local requirement _result=0
+	for requirement in "$@"; do
+		if ! _binary_exists "${requirement}"; then
+			_result=1
+		fi
+	done
+	if [[ ${_result} -gt 0 ]]; then
+		_log_warning "Without '${!#}' installed, this completion won't be too useful."
+	fi
+	return "${_result}"
+}
+
+function _bash-it-completion-helper-sufficient() {
+	local completion _result=0
+	for completion in "$@"; do
+		if _completion_exists "${completion}"; then
+			_result=1
+		fi
+	done
+	if [[ ${_result} -gt 0 ]]; then
+		_log_warning "completion already loaded - this usually means it is safe to stop using this completion."
+	fi
+	return "${_result}"
+}