Made create_offlinerepo.sh more tool-like

create_offlinerepo.sh

 #!/bin/bash
 
 set -e
-set -x
 
-iso_file="ubuntu-18.04.1-desktop-amd64.iso"
+usage () {
+	echo "usage: create_offlinerepo.sh repodir isofile [list of packages]" >&2
+	echo >&2
+	echo "Downloads all packages required to fully update the system in 'isofile' and" >&2
+	echo "to install the listed packages and adds them to the package archive in 'repodir'." >&2
+	exit 1
+}
+
+dest="$1"
+shift || usage
+iso_file="$1"
+shift || usage
+packages="$@"
+
 workspace="/workspace"
-dest="archive"
-packages="vim htop"
 
 rm -rf "$workspace"/offlinerepo
 mkdir -p "$workspace"/offlinerepo
@@ -23,6 +33,7 @@ apt-get -o Dir="$workspace"/offlinerepo/squashfs-root update
 
 {
 	cd "$dest"
+	rm -rf "$dest"/Packages.*
 	dpkg-scanpackages . | gzip > Packages.gz
 }