diff --git a/myfunctions.sh b/myfunctions.sh
new file mode 100644
index 0000000..2f23bc1
--- /dev/null
+++ b/myfunctions.sh
@@ -0,0 +1,13 @@
+# ecrire une fonction upper qui passe la chaine de caract_re
+# passée en param en majuscules
+function upper {
+   echo "$@" | tr [a-z] [A-Z]
+}
+
+function myerror {
+   code=$1
+   shift
+   msg="$*"
+   echo $msg
+   exit $code
+}
diff --git a/script.sh b/script.sh
new file mode 100644
index 0000000..a8e1a06
--- /dev/null
+++ b/script.sh
@@ -0,0 +1,16 @@
+#! /bin/bash
+
+set -u
+set -e
+
+source $(dirname $0)/myfunctions.sh
+
+if [ $# -ne 2 ] ; then
+   myerror 42 "Usage: $0 arg1 arg2"
+fi
+
+if [ $(whoami) != "root" ] ; then
+   myerror 43 "Please sudo first"
+fi
+
+echo "good job"
\ No newline at end of file