diff --git a/LICENSE b/LICENSE
index b0e20f5..72d799c 100644
--- a/LICENSE
+++ b/LICENSE
@@ -1,4 +1,4 @@
-Copyright (c) <year> <owner> All rights reserved.
+Copyright (c) 2021 Solène Rapenne All rights reserved.
 
 Redistribution and use in source and binary forms, with or without modification, are permitted provided that the following conditions are met:
 
diff --git a/README.md b/README.md
index fa1ad22..0f44860 100644
--- a/README.md
+++ b/README.md
@@ -1,3 +1,38 @@
-# pkgupdate
+# Presentation
 
-OpenBSD efficient stable updater
\ No newline at end of file
+**pkgupdate** is a simple shell script meant for OpenBSD users of the stable branchs (people following releases) to easily keep their packages up to date.
+
+It is meant to be run daily by cron on servers on at boot time for workstations (you can obviously configure it how you prefer).
+
+# How?
+
+**pkgupdate** uses 3 tricks to speed up the process, this is particularily important for workstations updating during the boot process:
+
+- fetch the index of packages and compare it between runs (using a cache in `/var/cache/pkgupdate/`)
+- if the index changed, which mean everytime a new package is updated, then it only try to update the packages available in the `packages-stable` directory
+- if curl is installed, use curl instead of ftp(1) command
+
+# Why?
+
+This tool is based on solene@ previous work [faster packages updates](https://dataswamp.org/~solene/2021-08-06-openbsd-pkgadd-tuning-updates.html) and [pkg_add performance analysis](https://dataswamp.org/~solene/2021-07-08-openbsd-pkg_add_performance_analysis.html).
+
+In my opinion, workstations should be updated as soon as possible, at boot time, to update packages at boot before using anything from the user session, avoiding a boring reboot.
+
+As for servers, making the process faster is always welcome.
+
+# Setup
+
+First, use `git clone https://tildegit.org/solene/pkgupdate.git` and copy `pkgupdate` in `/usr/local/bin/`.
+
+Best way to manage this is to use root's crontab.  As root, type `crontab -e` to edit its tab.
+
+```
+# for updating on boot
+@reboot /usr/local/bin/pkgupdate
+
+# for updating every hour
+@hourly /usr/local/bin/pkgupdate
+
+# for updating every 6 hours
+0 */6 * * * /usr/local/bin/pkgupdate
+```
diff --git a/pkgupdate b/pkgupdate
new file mode 100644
index 0000000..23512cc
--- /dev/null
+++ b/pkgupdate
@@ -0,0 +1,88 @@
+#!/bin/sh
+
+INSTALLURL=$(grep -v ^# /etc/installurl | head -n 1)
+export PKG_PATH="${INSTALLURL}/$(uname -r)/packages-stable/$(machine)/"
+
+CACHE_DIR=/var/cache/pkgupdate/
+
+
+def_curl() {
+    if type curl 2> /dev/null >/dev/null
+    then
+    	export FETCH_CMD="/usr/local/bin/curl -L -s -q -N"
+    fi
+}
+
+check_cache() {
+    # creating cache directory
+    if ! install -d -o root -g wheel -m 755 ${CACHE_DIR}
+    then
+        echo "Error when creating the cache directory ${CACHE_DIR}"
+        exit 1
+    fi
+
+    ftp -o - "$PKG_PATH" 2>/dev/null | grep tgz > ${CACHE_DIR}/index.now
+    if [ $? -eq 0 ]
+    then
+
+        # check if we already used pkgupdate
+        if [ ! -f ${CACHE_DIR}/index.previous ]
+        then
+            # first time we use it
+            mv ${CACHE_DIR}/index.now ${CACHE_DIR}/index.previous
+        else
+            # compare current output with the previous one
+            # if they are identical, no changes has been done
+            if cmp ${CACHE_DIR}/index.now ${CACHE_DIR}/index.previous
+            then
+                rm ${CACHE_DIR}/index.now
+                echo "No changes on the mirror."
+                exit 0
+            fi
+        fi
+    else
+        echo "error when downloading the index, return $?"
+        exit 1
+    fi
+}
+
+do_http() {
+    echo "Updating using $1 protocol"
+    check_cache
+    def_curl
+    pkg_add -u 2>&1 | grep -v "^Couldn't find updates for "
+}
+
+do_https() {
+    do_http "https://"
+}
+
+unsupported() {
+    echo "protocol not supported: $1"
+    exit 1
+}
+
+unknown() {
+    echo "protocol not known for $1"
+    exit 1
+}
+
+
+if sysctl kern.version | grep -- "-current" >/dev/null
+then
+    echo "You can't use this on -current"
+    exit 1
+fi
+
+case "$INSTALLURL" in
+	http://*) do_http "http://"
+		;;
+	https://*) do_https "https://"
+		;;
+	ftp://*) unsupported ftp
+		;;
+	scp://*) unsupported scp
+		;;
+	*) unknown "$INSTALLURL"
+		;;
+esac