From e7aa72160f854bd255373a5a6bd9981c4977c46d Mon Sep 17 00:00:00 2001
From: "Andrew J. Hesford" <ajh@sideband.org>
Date: Mon, 16 Dec 2019 11:19:53 -0500
Subject: [PATCH] Support suffix matching in the same style as prefix matching.

---
 README.md                  | 10 ++++++++++
 man/zfs-prune-snapshots.1  |  7 +++++++
 man/zfs-prune-snapshots.md |  7 +++++++
 zfs-prune-snapshots        | 17 +++++++++++++++--
 4 files changed, 39 insertions(+), 2 deletions(-)

diff --git a/README.md b/README.md
index 8adad4d..d14e7b1 100644
--- a/README.md
+++ b/README.md
@@ -26,6 +26,11 @@ with the string "autosnap_"
 
     zfs-prune-snapshots -p 'autosnap_' 1M zones
 
+Remove snapshots older than two months on the tank pool that end
+with the string "_frequent"
+
+    zfs-prune-snapshots -s '_frequent' 2M tank
+
 Timespec
 --------
 
@@ -64,6 +69,10 @@ Usage
         remove snapshots older than a month on the zones pool that start
         with the string "autosnap_"
 
+        # zfs-prune-snapshots -s '_frequent' 2M tank
+        remove snapshots older than two months on the tank pool that end
+        with the string "_frequent"
+
     timespec
         the first argument denotes how old a snapshot must be for it to
         be considered for deletion - possible specifiers are
@@ -80,6 +89,7 @@ Usage
         -h             print this message and exit
         -n             dry-run, don't actually delete snapshots
         -p <prefix>    snapshot prefix string to match
+        -s <suffix>    snapshot suffix string to match
         -q             quiet, do not printout removed snapshots
         -v             increase verbosity
         -V             print the version number and exit
diff --git a/man/zfs-prune-snapshots.1 b/man/zfs-prune-snapshots.1
index 6ae4cf6..73b7a6c 100644
--- a/man/zfs-prune-snapshots.1
+++ b/man/zfs-prune-snapshots.1
@@ -21,6 +21,9 @@ dry\-run, don't actually delete snapshots
 \fB\fC\-p <prefix>\fR
 snapshot prefix string to match
 .TP
+\fB\fC\-s <suffix>\fR
+snapshot suffix string to match
+.TP
 \fB\fC\-q\fR
 quiet, do not printout removed snapshots
 .TP
@@ -65,6 +68,10 @@ tank2/backup
 \fB\fCzfs\-prune\-snapshots \-p 'autosnap_' 1M zones\fR
 Remove snapshots older than a month on the zones pool that start with the
 string \fB\fC"autosnap_"\fR
+.TP
+\fB\fCzfs\-prune\-snapshots \-s '_frequent' 2M tank\fR
+Remove snapshots older than two months on the tank pool that end with the
+string \fB\fC"_frequent"\fR
 .SH BUGS
 .PP
 \[la]https://github.com/bahamas10/zfs-prune-snapshots\[ra]
diff --git a/man/zfs-prune-snapshots.md b/man/zfs-prune-snapshots.md
index f6a5ee3..598c8a4 100644
--- a/man/zfs-prune-snapshots.md
+++ b/man/zfs-prune-snapshots.md
@@ -30,6 +30,9 @@ OPTIONS
 `-p <prefix>`
   snapshot prefix string to match
 
+`-s <suffix>`
+  snapshot suffix string to match
+
 `-q`
   quiet, do not printout removed snapshots
 
@@ -77,6 +80,10 @@ EXAMPLES
   Remove snapshots older than a month on the zones pool that start with the
   string `"autosnap_"`
 
+`zfs-prune-snapshots -s '_frequent' 2M tank`
+  Remove snapshots older than two months on the tank pool that end with the
+  string `"_frequent"`
+
 BUGS
 ----
 
diff --git a/zfs-prune-snapshots b/zfs-prune-snapshots
index 857bb7b..7f35834 100755
--- a/zfs-prune-snapshots
+++ b/zfs-prune-snapshots
@@ -11,7 +11,7 @@ VERSION='v1.0.1'
 usage() {
 	local prog=${0##*/}
 	cat <<-EOF
-	usage: $prog [-hnv] [-p <prefix] <time> [[dataset1] ...]
+	usage: $prog [-hnv] [-p <prefix>] [-s <suffix>] <time> [[dataset1] ...]
 
 	remove snapshots from one or more zpools that match given criteria
 
@@ -32,6 +32,10 @@ usage() {
 	    remove snapshots older than a month on the zones pool that start
 	    with the string "autosnap_"
 
+	    # $prog -s '_frequent' 2M tank
+	    remove snapshots older than two months on the tank pool that end
+	    with the string "_frequent"
+
 	timespec
 	    the first argument denotes how old a snapshot must be for it to
 	    be considered for deletion - possible specifiers are
@@ -48,6 +52,7 @@ usage() {
 	    -h             print this message and exit
 	    -n             dry-run, don't actually delete snapshots
 	    -p <prefix>    snapshot prefix string to match
+	    -s <suffix>    snapshot suffix string to match
 	    -q             quiet, do not printout removed snapshots
 	    -v             increase verbosity
 	    -V             print the version number and exit
@@ -93,12 +98,14 @@ human() {
 dryrun=false
 verbosity=0
 prefix=
+suffix=
 quiet=false
-while getopts 'hnqp:vV' option; do
+while getopts 'hnqp:s:vV' option; do
 	case "$option" in
 		h) usage; exit 0;;
 		n) dryrun=true;;
 		p) prefix=$OPTARG;;
+		s) suffix=$OPTARG;;
 		q) quiet=true;;
 		v) ((verbosity++));;
 		V) echo "$VERSION"; exit 0;;
@@ -148,6 +155,12 @@ while read -r creation snapshot; do
 		continue
 	fi
 
+	# ensure optional suffix matches
+	if [[ -n $suffix && $suffix != "${snapname: -${#suffix}}" ]]; then
+		debug "skipping $snapshot: doesn't match suffix $suffix"
+		continue
+	fi
+
 	# ensure snapshot is older than the cutoff time
 	delta=$((now - creation))
 	human=$(human "$delta")