1 files changed, 103 insertions, 0 deletions
diff --git a/bin/ootb b/bin/ootb
new file mode 100755
index 0000000..3aa58db
--- /dev/null
+++ b/bin/ootb
@@ -0,0 +1,103 @@
+#!/bin/sh
+set -eu
+
+usage() {
+	cat <<-'EOF'
+		Usage:
+		  ootb BUILD_DIRECTORY < FILE...
+		  ootb -h
+	EOF
+}
+
+help() {
+	cat <<-'EOF'
+
+
+		Options:
+		  -h, --help          show this message
+
+		  BUILD_DIRECTORY    the path of the build directory
+		  FILE               the files to be linked
+
+
+		Create a directory out of symlinks of the given files.
+
+		The goal is to enable parallel build directories to coexist,
+		so that one do *O*ut *O*f *T*ree *B*uilds without requiring the
+		build system or the project to explicitly support it.
+
+		If a repository contains the files:
+
+		  .git/
+		  Makefile
+		  README.md
+		  src/
+		    file1.ext
+		    file2.ext
+
+		Running `git ls-files | ootb build-1/` would create the
+		'build-1/' directory with:
+
+		  build-1/
+		    Makefile -> /absolute/path/to/Makefile
+		    README.md -> /absolute/path/to/README.md
+		    src/
+		      file1.ext -> /absolute/path/to/file1.ext
+		      file2.ext -> /absolute/path/to/file2.ext
+
+		With that one can `cd build-1/` and run builds there, without
+		the build artifacts littering the source tree.  Also, one could
+		create a build-2/ directory, where different compiler flags or
+		build options are given, such as debug/release, while sharing the
+		underlying source code.
+
+
+		Examples:
+
+		  Create a 'build/' directory with the files from the Git repository:
+
+		    $ git ls-files | ootb build/
+	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 $((OPTIND - 1))
+
+
+BUILD_DIRECTORY="${1:-}"
+eval "$(assert-arg "$BUILD_DIRECTORY" 'BUILD_DIRECTORY')"
+mkdir -p "$BUILD_DIRECTORY"
+
+
+while read -r f; do
+	mkdir -p "$BUILD_DIRECTORY"/"$(dirname "$f")"
+	ln -fs "$PWD"/"$f" "$BUILD_DIRECTORY"/"$f"
+done