From fcd6f8887056609f784c5261c892bae72dbc0b34 Mon Sep 17 00:00:00 2001
From: Horea Christian <chr@chymera.eu>
Date: Thu, 15 Dec 2022 17:41:42 -0500
Subject: [PATCH] Added automatic extraction script

---
 README.md   | 10 ++++++++--
 exstage4.sh | 26 ++++++++++++++++++++++++++
 2 files changed, 34 insertions(+), 2 deletions(-)
 create mode 100755 exstage4.sh

diff --git a/README.md b/README.md
index 73989b2..eea4021 100644
--- a/README.md
+++ b/README.md
@@ -61,7 +61,13 @@ mkstage4.sh [-q -c -b -l -k -p] [-s || -t <target-mountpoint>] [-e <additional e
 
 ## System Tarball Extraction
 
-### Single-threaded
+### Automatic (Multi-threaded)
+
+We provide a script for convenient extraction, `exstage4`, which is shipped with this package.
+Currently it simply automates the Multi-threaded extraction selection listed below and otherwise has no functionality except checking that the file name looks sane.
+If in doubt, use one of the explicit extraction methods described below.
+
+### Explicit Single-threaded
 
 Tarballs created with mkstage4 can be extracted with:
 
@@ -78,7 +84,7 @@ tar xvjpf archive_name.tar.bz2.kmod
 tar xvjpf archive_name.tar.bz2.ksrc
 ```
 
-### Multi-threaded
+### Explicit Multi-threaded
 
 If you have a parallel de/compressor installed, you can extract the archive with one of the respective commands:
 
diff --git a/exstage4.sh b/exstage4.sh
new file mode 100755
index 0000000..4a7bafc
--- /dev/null
+++ b/exstage4.sh
@@ -0,0 +1,26 @@
+#!/usr/bin/env bash
+
+STAGE_FILE=${1}
+
+echo "${STAGE_FILE}"
+
+EXT="${STAGE_FILE##*.}"
+
+TARFILE="${STAGE_FILE%%.$EXT}"
+TAREXT="${TARFILE##*.}"
+
+if [[ $TAREXT != "tar" ]]; then
+	echo "The stage file you are trying to unpack (\`$STAGE_FILE\`) does not appear to be an archived TAR file"
+else
+	echo "Extracting \`${STAGE_FILE}\` inplace."
+fi
+
+if [ $EXT == "xz" ]; then
+	tar -I 'xz -T0' -xvf "${STAGE_FILE}" --xattrs-include='*.*' --numeric-owner
+elif [ $EXT == "bz2" ]; then
+	tar -I pbzip2 -xvf "${STAGE_FILE}" --xattrs-include='*.*' --numeric-owner
+elif [ $EXT == "gz" ]; then
+	tar -I unpigz -xvf "${STAGE_FILE}" --xattrs-include='*.*' --numeric-owner
+else
+	echo "Not sure how to unpack \`${STAGE_FILE}\`"
+fi