add travis autobuild scripts (courtesy of EmuTOS project)

.travis/generate-purge.sh

@@ -0,0 +1,53 @@
+#!/bin/bash -u
+# -u: Treat unset variables as an error when substituting.
+
+# Purpose: Purge old snapshots
+# Input: output of lftp "ls" command
+# Output: lftp "rm -r" commands
+
+# Number of days of retention before purge
+days_retention=7
+
+# But always keep a minimal number of snapshots
+min_keep=5
+
+# Every snapshot up to this day will be purged
+last_day_purge=$(date -u +%Y%m%d --date "$days_retention days ago")
+
+# Current number of snapshots kept
+n=0
+
+# Read each remote file, as output from lftp "ls" command
+while read flags links user group size month day hour f
+do
+  # Skip non-snapshots
+  if [[ ! $f =~ ^[0-9]*-[0-9]*-[0-9a-z]* ]]
+  then
+    continue
+  fi
+
+  echo $f
+
+  # Then reverse sort to have last snapshots first
+done | sort -r | while read f
+do
+  # This is one more snapshot
+  (( n++ ))
+
+  # Do not purge until minimal number of snapshots
+  if [ $n -le $min_keep ]
+  then
+    echo "echo '#keep $f'"
+    continue
+  fi
+
+  # Purge old snapshots
+  day=$(echo $f | cut -d - -f 1)
+  if [ $day -le $last_day_purge ]
+  then
+    echo "echo 'rm -r $f'"
+    echo "rm -r $f"
+  else
+    echo "echo '#keep $f'"
+  fi
+done