From f4b0a07091e4a10395f98726bc075f2eaae1469f Mon Sep 17 00:00:00 2001
From: Lorenzo Beretta <vc.net.loreb@gmail.com>
Date: Wed, 9 Jun 2021 23:24:12 +0200
Subject: [PATCH] Translate to (99%) POSIX sh

The missing 1% is that POSIX doesn't have "local" or a __clean__ (non kludgy) equivalent.
Other than that I'm checking the return value of everything that could conceivably fail, except for `$(pwd)` which imho could be replaced by `$PWD`.

Autocompletion is commented out in case you use a non-bash shell which has autocompletion (OpenBSD's ksh at least)
and feel like translating that.
---
 upto-posix.sh | 47 +++++++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 47 insertions(+)
 create mode 100644 upto-posix.sh

diff --git a/upto-posix.sh b/upto-posix.sh
new file mode 100644
index 0000000..88ee806
--- /dev/null
+++ b/upto-posix.sh
@@ -0,0 +1,47 @@
+#!/bin/sh
+# shellcheck "$0"
+upto() {
+	# "local" isn't POSIX technically...
+	local EXPRESSION="$1"
+	if [ -z "$EXPRESSION" ]; then
+		echo "A folder expression must be provided." >&2
+		return 1
+	fi
+	if [ "$EXPRESSION" = "/" ]; then
+		cd "/"
+		return #0
+	fi
+	local CURRENT_FOLDER="$(pwd)" # why not $PWD?
+	local MATCHED_DIR=""
+	local MATCHING=true
+
+	while [ "$MATCHING" = true ]; do
+		case "$CURRENT_FOLDER" in
+			(*${EXPRESSION}*)
+				MATCHED_DIR="$CURRENT_FOLDER"
+				CURRENT_FOLDER=$(dirname "$CURRENT_FOLDER") || return
+				;;
+			(*)
+				MATCHING=false ;;
+		esac
+	done
+	if [ -n "$MATCHED_DIR" ]; then
+		cd "$MATCHED_DIR"
+		return #0
+	else
+		echo "No Match." >&2
+		return 1
+	fi
+}
+
+# complete upto
+#_upto () {
+#	# necessary locals for _init_completion
+#	local cur prev words cword
+#	_init_completion || return
+#
+#	COMPREPLY+=( $( compgen -W "$( echo ${PWD//\// } )" -- $cur ) )
+#}
+## This complete scheme relies on bash_completion, and the subsequent
+## _init_completion function to work.
+#declare -f _init_completion > /dev/null && complete -F _upto upto