Merge branch 'release/1.2.0'

Author: Enrico M. Crisostomo

README.md

@@ -7,21 +7,30 @@ tm-cleanup.sh
 -------------
 
 `tm-cleanup.sh` is a ZSH script that lists the completed Time Machine snapshots
-and deletes those that are oldest that a specified number of days.  The default
-threshold is 30 days.
+and deletes those that satisfy the specified criteria.  Two types of deletion
+criteria exist:
+
+  * By date: snapshots that are older than a specified number of days are
+    deleted.  The default threshold is 30 days.
+
+  * By number: a maximum number of snapshots is retained and oldest snapshots
+  are deleted.
+
+Only one deletion criteria can be specified.
 
 The syntax of `tm-cleanup.sh` is the following:
 
 ```
-$ tm-cleanup.sh [-d days] [-f] [-x]
+$ tm-cleanup.sh (-d days | -n number) [-f] [-x]
 $ tm-cleanup.sh [-h]
 ```
 
 where
 
-  * By default backups older than 30 days will be deleted.  If `-d` is
-    speficied, backups older than the specified number of days will be deleted.
-    `days` is an unsigned positive integer number.
+  * If `-d` is specified, backups older than the specified number of days will
+    be deleted.  `days` is a positive integer number.
+  * `-n` specifies the number of backups to retain.  `number` is a positive
+    integer number.
   * By default, `tm-cleanup.sh` exits and prints an error message if a Time
     Machine backup is currently in progress.  `-f` forces the backup deletion
     concurrently.
@@ -30,18 +39,17 @@ where
     be performed without actually performing any.
 
 This script *never* deletes the latest snapshot, no matter the value of the
-`days` option.
+`-d` or `-n` options.
 
 Installation
 ------------
 
 The scripts require no installation: they can be downloaded and run from any
-location.
-However, this repository provides an installation script that creates
-symbolic links to `/usr/local/bin`, a directory which is included by default
-in the `${PATH}` of any OS X user.
-Installing the symbolic links has the advantage of always providing the current
-version of the scripts on the `${PATH}` when the local repository is updated.
+location.  However, this repository provides an installation script that creates
+symbolic links to `/usr/local/bin`, a directory which is included by default in
+the `${PATH}` of any OS X user.  Installing the symbolic links has the advantage
+of always providing the current version of the scripts on the `${PATH}` when the
+local repository is updated.
 
 To install the symbolic links:
 
@@ -74,7 +82,7 @@ Bug reports can be sent directly to the authors.
 
 -----
 
-Copyright (C) 2015 Enrico M. Crisostomo
+Copyright (C) 2016 Enrico M. Crisostomo
 
 This program is free software; you can redistribute it and/or modify
 it under the terms of the GNU General Public License as published by

tm-cleanup.sh

@@ -1,7 +1,7 @@
 #!/bin/zsh
 # -*- coding: utf-8; tab-width: 2; indent-tabs-mode: nil; sh-basic-offset: 2; sh-indentation: 2; -*- vim:fenc=utf-8:et:sw=2:ts=2:sts=2
 #
-# Copyright (C) 2015, Enrico M. Crisostomo
+# Copyright (C) 2016, Enrico M. Crisostomo
 #
 # This program is free software; you can redistribute it and/or modify
 # it under the terms of the GNU General Public License as published by
@@ -24,7 +24,7 @@ set -o errexit
 set -o nounset
 
 PROGNAME=$0
-VERSION=1.1.0
+VERSION=1.2.0
 
 command -v tmutil > /dev/null 2>&1 || {
   >&2 print -- Cannot find tmutil.
@@ -36,7 +36,7 @@ print_usage()
   print -- "${PROGNAME} ${VERSION}"
   print
   print -- "Usage:"
-  print -- "${PROGNAME} [-d days] [-n number] [-f] [-x]"
+  print -- "${PROGNAME} (-d days | -n number) [-f] [-x]"
   print -- "${PROGNAME} [-h]"
   print
   print -- "Options:"
@@ -59,9 +59,10 @@ FORCE_EXECUTION=0
 # Execution modes
 #   - 0: number of days
 #   - 1: number of backups
-MODE_DAYS=0
-MODE_BACKUPS=1
-typeset -i EXECUTION_MODE=-1
+MODE_DAYS=1
+MODE_BACKUPS=2
+MODE_UNKNOWN=0
+typeset -i EXECUTION_MODE=${MODE_UNKNOWN}
 typeset -i ARGS_PROCESSED=0
 
 parse_opts()
@@ -75,14 +76,14 @@ parse_opts()
         ;;
       d)
         DAYS_TO_KEEP=${OPTARG}
-        EXECUTION_MODE=${MODE_DAYS}
+        EXECUTION_MODE=$((MODE_DAYS | EXECUTION_MODE))
         ;;
       f)
         FORCE_EXECUTION=1
         ;;
       n)
         NUMBER_TO_KEEP=${OPTARG}
-        EXECUTION_MODE=${MODE_BACKUPS}
+        EXECUTION_MODE=$((MODE_BACKUPS | EXECUTION_MODE))
         ;;
       x)
         DRY_RUN=1
@@ -197,6 +198,18 @@ then
   exit 4
 fi
 
+if (( ${EXECUTION_MODE} == ${MODE_UNKNOWN} ))
+then
+  >&2 print -- No mode specified. Exiting.
+  exit 2
+fi
+
+if (( EXECUTION_MODE & (EXECUTION_MODE - 1) ))
+then
+  >&2 print -- Only one mode can be specified. Exiting.
+  exit 2
+fi
+
 # Get the full list of backups from tmutil
 TM_BACKUPS=( "${(ps:\n:)$(tmutil listbackups)}" )
 
@@ -211,4 +224,8 @@ case ${EXECUTION_MODE} in
   ${MODE_BACKUPS})
     process_by_backups
     ;;
+  *)
+    >&2 print -- Unexpected mode. Exiting.
+    exit 4
+    ;;
 esac