diff --git a/contrib/tig-completion.bash b/contrib/tig-completion.bash
index 78c86d53f..e7756d949 100755
--- a/contrib/tig-completion.bash
+++ b/contrib/tig-completion.bash
@@ -1,276 +1,85 @@
-##
-# bash completion support for tig
-#
+# bash/zsh completion for tig
+# 
+# Copyright (C) 2019 Roland Hieber, Pengutronix
 # Copyright (C) 2007-2010 Jonas fonseca
-# Copyright (C) 2006,2007 Shawn Pearce
 #
-# Based git's git-completion.sh: http://repo.or.cz/w/git/fastimport.git
+# This program is free software; you can redistribute it and/or
+# modify it under the terms of the GNU General Public License as
+# published by the Free Software Foundation; either version 2 of
+# the License, or (at your option) any later version.
 #
-# The contained completion routines provide support for completing:
+# This completion builds upon the git completion (>= git 1.17.11),
+# which most tig users should already have available at this point.
+# To use these routines:
 #
-#    *) local and remote branch names
-#    *) local and remote tag names
-#    *) tig 'subcommands'
-#    *) tree paths within 'ref:path/to/file' expressions
+#    1) Copy this file to somewhere (e.g. ~/.bash_completion.d/tig).
 #
-# To use these routines:
+#    2) Add the following line to your .bashrc:
 #
-#    1) Copy this file to somewhere (e.g. ~/.tig-completion.sh).
-#    2) Added the following line to your .bashrc:
-#        source ~/.tig-completion.sh
+#           source ~/.bash_completion.d/tig
+#
+#       Note that most Linux distributions source everything in
+#       ~/.bash_completion.d/ automatically at bash startup, so you
+#       have to source this script manually only in shells that were
+#       already running before.
 #
 #    3) You may want to make sure the git executable is available
 #       in your PATH before this script is sourced, as some caching
 #       is performed while the script loads.  If git isn't found
 #       at source time then all lookups will be done on demand,
 #       which may be slightly slower.
-#
-
-__tigdir ()
-{
-	if [ -z "$1" ]; then
-		if [ -n "$__git_dir" ]; then
-			echo "$__git_dir"
-		elif [ -d .git ]; then
-			echo .git
-		else
-			git rev-parse --git-dir 2>/dev/null
-		fi
-	elif [ -d "$1/.git" ]; then
-		echo "$1/.git"
-	else
-		echo "$1"
-	fi
-}
-
-_tigcomp ()
-{
-	local all c s=$'\n' IFS=' '$'\t'$'\n'
-	local cur="${COMP_WORDS[COMP_CWORD]}"
-	if [ $# -gt 2 ]; then
-		cur="$3"
-	fi
-	for c in $1; do
-		case "$c$4" in
-		--*=*) all="$all$c$4$s" ;;
-		*.)    all="$all$c$4$s" ;;
-		*)     all="$all$c$4 $s" ;;
-		esac
-	done
-	IFS=$s
-	COMPREPLY=($(compgen -P "$2" -W "$all" -- "$cur"))
-	return
-}
 
-__tig_refs ()
-{
-	local cmd i is_hash=y dir="$(__tigdir "$1")"
-	if [ -d "$dir" ]; then
-		for i in HEAD FETCH_HEAD ORIG_HEAD MERGE_HEAD; do
-			if [ -e "$dir/$i" ]; then echo $i; fi
-		done
-		for i in $(git --git-dir="$dir" \
-			for-each-ref --format='%(refname)' \
-			refs/tags refs/heads refs/remotes); do
-			case "$i" in
-				refs/tags/*)    echo "${i#refs/tags/}" ;;
-				refs/heads/*)   echo "${i#refs/heads/}" ;;
-				refs/remotes/*) echo "${i#refs/remotes/}" ;;
-				*)              echo "$i" ;;
-			esac
-		done
-		return
-	fi
-	for i in $(git-ls-remote "$dir" 2>/dev/null); do
-		case "$is_hash,$i" in
-		y,*) is_hash=n ;;
-		n,*^{}) is_hash=y ;;
-		n,refs/tags/*) is_hash=y; echo "${i#refs/tags/}" ;;
-		n,refs/heads/*) is_hash=y; echo "${i#refs/heads/}" ;;
-		n,refs/remotes/*) is_hash=y; echo "${i#refs/remotes/}" ;;
-		n,*) is_hash=y; echo "$i" ;;
-		esac
-	done
-}
-
-__tig_complete_file ()
-{
-	local pfx ls ref cur="${COMP_WORDS[COMP_CWORD]}"
-	case "$cur" in
-	?*:*)
-		ref="${cur%%:*}"
-		cur="${cur#*:}"
-		case "$cur" in
-		?*/*)
-			pfx="${cur%/*}"
-			cur="${cur##*/}"
-			ls="$ref:$pfx"
-			pfx="$pfx/"
-			;;
-		*)
-			ls="$ref"
-			;;
-	    esac
-		COMPREPLY=($(compgen -P "$pfx" \
-			-W "$(git --git-dir="$(__tigdir)" ls-tree "$ls" \
-				| sed '/^100... blob /s,^.*	,,
-				       /^040000 tree /{
-					   s,^.*	,,
-					   s,$,/,
-				       }
-				       s/^.*	//')" \
-			-- "$cur"))
-		;;
-	*)
-		_tigcomp "$(__tig_refs)"
-		;;
-	esac
-}
-
-__tig_complete_revlist ()
-{
-	local pfx cur="${COMP_WORDS[COMP_CWORD]}"
-	case "$cur" in
-	*...*)
-		pfx="${cur%...*}..."
-		cur="${cur#*...}"
-		_tigcomp "$(__tig_refs)" "$pfx" "$cur"
-		;;
-	*..*)
-		pfx="${cur%..*}.."
-		cur="${cur#*..}"
-		_tigcomp "$(__tig_refs)" "$pfx" "$cur"
-		;;
-	*.)
-		_tigcomp "$cur."
-		;;
-	*)
-		_tigcomp "$(__tig_refs)"
-		;;
-	esac
-}
-
-_tig_options ()
-{
-	local cur="${COMP_WORDS[COMP_CWORD]}"
-	case "$cur" in
-	--pretty=*)
-		_tigcomp "
-			oneline short medium full fuller email raw
-			" "" "${cur##--pretty=}"
-		return
-		;;
-	--*)
-		_tigcomp "
-			--max-count= --max-age= --since= --after=
-			--min-age= --before= --until=
-			--root --not --topo-order --date-order
-			--no-merges
-			--abbrev-commit --abbrev=
-			--relative-date
-			--author= --committer= --grep=
-			--all-match
-			--pretty= --name-status --name-only
-			--not --all
-			--help --version
-			"
-		return
-		;;
-	-*)
-		_tigcomp "-v -h"
-		return
-		;;
-	esac
-	__tig_complete_revlist
-}
-
-_tig_blame ()
-{
-	local reply="" ref=HEAD cur="${COMP_WORDS[COMP_CWORD]}" p=""
-	local pfx=$(git rev-parse --show-prefix 2>/dev/null)
-
-	if test "$COMP_CWORD" -lt 3; then
-		_tigcomp "$(__tig_refs)"
-	else
-		ref="${COMP_WORDS[2]}"
-	fi
-
-	case "$cur" in
-		*/)	p=${cur%/} ;;
-		*/*)	p=${cur%/*} ;;
-		*)	p= ;;
-	esac
-
-	i=${#COMPREPLY[@]}
-	local IFS=$'\n'
-	for c in $(git --git-dir="$(__tigdir)" ls-tree "$ref:$pfx$p" 2>/dev/null |
-		sed -n '/^100... blob /{
-			s,^.*	,,
-			s,$, ,
-			p
-		}
-		/^040000 tree /{
-			s,^.*	,,
-			s,$,/,
-			p
-		}')
-	do
-		c="${p:+$p/}$c"
-		if [[ "$c" == "$cur"* ]]; then
-			COMPREPLY[i++]=$c
-		fi
-	done
-}
-
-_tig_show ()
-{
-	local cur="${COMP_WORDS[COMP_CWORD]}"
-	case "$cur" in
-	--pretty=*)
-		_tigcomp "
-			oneline short medium full fuller email raw
-			" "" "${cur##--pretty=}"
-		return
-		;;
-	--*)
-		_tigcomp "--pretty="
-		return
-		;;
-	esac
-	__tig_complete_file
-}
-
-_tig ()
-{
-	local i c=1 command __tig_dir
-
-	while [ $c -lt $COMP_CWORD ]; do
-		i="${COMP_WORDS[c]}"
+__tig_options="
+	-v --version
+	-h --help
+	-C
+	--
+	+
+"
+__tig_commands="
+	blame
+	grep
+	log
+	reflog
+	refs
+	stash
+	status
+	show
+"
+
+_tig() {
+	# parse already existing parameters
+	local i c=1 command
+	while [ $c -lt $cword ]; do
+		i="${words[c]}"
 		case "$i" in
-		--) command="log"; break;;
-		-*) ;;
-		*) command="$i"; break ;;
+		--)	command="log"; break;;
+		-*)	continue;;
+		*)	command="$i"; break ;;
 		esac
 		c=$((++c))
 	done
 
-	if [ $c -eq $COMP_CWORD -a -z "$command" ]; then
-		case "${COMP_WORDS[COMP_CWORD]}" in
-		--*=*) COMPREPLY=() ;;
-		-*)   _tig_options ;;
-		*)    _tigcomp "blame status show log stash grep $(__tig_refs)" ;;
-		esac
-		return
-	fi
+	# options -- only before command
+	case "$command$cur" in
+		-C*)
+			COMPREPLY=( $(compgen -d -P '-C' -- ${cur##-C}) )
+			return
+			;;
+	esac
 
+	# commands
 	case "$command" in
-	blame)  _tig_blame ;;
-	show)   _tig_show ;;
-	status) ;;
-	*)	_tigcomp "
-			$(__tig_complete_file)
-			$(__tig_refs)
-		" ;;
+		refs|status|stash)
+			COMPREPLY=( $(compgen -W "$__tig_options" -- "$cur") )
+			;;
+		"")
+			__git_complete_command log
+			__gitcompappend "$(compgen -W "$__tig_options $__tig_commands" -- "$cur")"
+			;;
+		*)
+			__git_complete_command $command
+			;;
 	esac
 }
 
@@ -281,11 +90,13 @@ if [ -n "$ZSH_VERSION" ]; then
 	bashcompinit
 fi
 
-complete -o default -o nospace -F _tig tig
+# we use internal git-completion functions, so wrap _tig for all necessary
+# variables (like cword and prev) to be defined
+__git_complete tig _tig 
 
 # The following are necessary only for Cygwin, and only are needed
 # when the user has tab-completed the executable name and consequently
 # included the '.exe' suffix.
 if [ Cygwin = "$(uname -o 2>/dev/null)" ]; then
-	complete -o default -o nospace -F _tig tig.exe
+	__git_complete tig.exe _tig
 fi