support alignment of weeks to 1st of each monthHEADmaster

1 files changed, 13 insertions, 6 deletions

diff --git a/backomp b/backomp
index 8ae4f72..022665d 100755
--- a/backomp
+++ b/backomp
@@ -43,10 +43,12 @@ BEGIN {
 	if ("w" in ret)
 		after_w = ("M" in ret) ? "M" : "y"
 
-	split("mon tue wed thu fri sat sun", arr)
-	for (i in arr)
-		arr2[arr[i]] = i - 1
-	wshift = (10 - arr2[opt_week_start])*24*60*60
+	if (opt_week_start) {
+		split("mon tue wed thu fri sat sun", arr)
+		for (i in arr)
+			arr2[arr[i]] = i - 1
+		wshift = (10 - arr2[opt_week_start])*24*60*60
+	}
 }
 
 !n_buckets || keep_first && NR == 1 {
@@ -59,8 +61,9 @@ n_buckets {
 
 	bt["h"] = flr(t, 60*60)
 	bt["d"] = flr(t, 24*60*60)
-	bt["w"] = flr(t + wshift, 7*24*60*60) - wshift
 	bt["M"] = mstart(t)
+	d = wshift ? wshift : -bt["M"]
+	bt["w"] = flr(t + d, 7*24*60*60) - d
 	bt["y"] = ystart(t)
 
 	for (i = 1; i <= n_buckets; ++i) {
@@ -380,6 +383,10 @@ backup() {
 		err "invalid \$retain setting: ${retain}"
 		return 1
 	fi
+	if [[ ! "${week_start}" =~ ^(|mon|tue|wed|thu|fri|sat|sun)$ ]]; then
+		err "invalid \$week_start setting: ${week_start}"
+		return 1
+	fi
 
 	if [[ -n "${dest_path}" ]]; then
 		filter snaps snaps 'post-snapshot awk prefilter' \
@@ -395,7 +402,7 @@ backup() {
 declare -A def_opts=(
 	['retain']= # e.g. *h or 24h7d4w12M5y or 24^h10d*M
 	['interval']='0'
-	['week_start']='mon'
+	['week_start']='mon' # empty value aligns weeks to 1st of each month
 	['rsync_flags']='-a'
 	['rclone_flags']='--sftp-copy-is-hardlink'
 	['rclone_copy_command']='copy'