second commit

tools/idem_apt_install

@@ -0,0 +1,25 @@
+#!/bin/bash
+
+function usage() {
+    local BASECMD
+    BASECMD=$(basename "$0")
+    echo "usage: $BASECMD <packages...>"
+    echo 'idempotent debian package installation : update if necessary, install only if not yet done'
+    exit 1
+}
+
+[ "$(id -u)" -ne 0 ] && echo 'root privilege required' && exit 2
+[[ $# -lt 1 ]] && usage
+
+if [ "$(date --date='-12 hours' +%s)" -gt "$(date -d "$(stat -c %y /var/lib/apt/lists/partial)" +%s)" ]; then
+    echo "updating repositoring..."
+    apt-get update
+fi
+
+for i in "$@"; do
+    if ! dpkg -l "$i" 2>/dev/null | grep -q ^ii; then
+        sudo apt-get install -y "$i"
+    elif [ -n "${VERBOSE+x}" ] && $VERBOSE; then
+        echo "apt package <$i> already installed!"
+    fi
+done