.local/bin/without-env: Add working version

1 files changed, 76 insertions, 0 deletions

diff --git a/.local/bin/without-env b/.local/bin/without-env
new file mode 100755
index 0000000..45c41ca
--- /dev/null
+++ b/.local/bin/without-env
@@ -0,0 +1,76 @@
+#!/bin/sh
+set -eu
+
+usage() {
+	cat <<-'EOF'
+		Usage:
+		  without-env ENVVAR PATH -- COMMAND...
+		  without-env [-h]
+	EOF
+}
+
+help() {
+	cat <<-'EOF'
+
+		Options:
+		  -h, --help    show this message
+
+		Examples:
+
+		  Execute "command -V" filtering ~/bin, to get where "w3m" is
+		  in $PATH, other than ~/bin:
+		    $ without-env PATH ~/bin -- command -v w3m
+
+		  Compile foo.c, excluding ~/.local/include
+		  from $C_INCLUDE_PATH:
+		    $ without-env C_INCLUDE_PATH ~/.local/include -- cc -co foo.o foo.c
+	EOF
+}
+
+for flag in "$@"; do
+	case "$flag" in
+		--)
+			break
+			;;
+		--help)
+			usage
+			help
+			exit
+			;;
+		*)
+			;;
+	esac
+done
+
+while getopts 'h' flag; do
+	case "$flag" in
+		h)
+			usage
+			help
+			exit
+			;;
+		*)
+			usage >&2
+			exit 2
+			;;
+	esac
+done
+shift $((OPTIND - 1))
+
+assert_arg() {
+	if [ -z "$1" ]; then
+		printf 'Missing %s\n' "$2" >&2
+		exit 2
+	fi
+}
+
+assert_arg "${1:-}" 'ENVVAR'
+assert_arg "${2:-}" 'PATH'
+assert_arg "${3:-}" '--'
+
+eval "export $1=\"\$(echo \"\$$1\" | sed \"s|\$2:||g\")\""
+shift # drop $1
+shift # drop $2
+shift # drop --
+
+"$@"