plugins/osx-timemachine: `shellcheck` && `shfmt`

Use bash functionality rather than external binaries. Alsö, if $SUDO_ASKPASS is set then pass -A to sudo.

clean_files.txt

@@ -103,6 +103,7 @@ plugins/available/jump.plugin.bash
 plugins/available/less-pretty-cat.plugin.bash
 plugins/available/node.plugin.bash
 plugins/available/nodenv.plugin.bash
+plugins/available/osx-timemachine.plugin.bash
 plugins/available/osx.plugin.bash
 plugins/available/percol.plugin.bash
 plugins/available/plenv.plugin.bash

plugins/available/osx-timemachine.plugin.bash

@@ -1,20 +1,26 @@
-cite about-plugin
+# shellcheck shell=bash
 about-plugin 'OS X Time Machine functions'
 
+if [[ "${OSTYPE}" != 'darwin'* ]]; then
+	_log_warning "This plugin only works with Mac OS X"
+	return 1
+fi
+
 function time-machine-destination() {
 	group "osx-timemachine"
 	about "Shows the OS X Time Machine destination/mount point"
 
-  echo $(tmutil destinationinfo | grep "Mount Point" | sed -e 's/Mount Point   : \(.*\)/\1/g')
+	tmutil destinationinfo | grep "Mount Point" | sed -e 's/Mount Point   : \(.*\)/\1/g'
 }
 
 function time-machine-list-machines() {
 	group "osx-timemachine"
 	about "Lists the OS X Time Machine machines on the backup volume"
 
-  local tmdest="$(time-machine-destination)/Backups.backupdb"
+	local tmdest
+	tmdest="$(time-machine-destination)/Backups.backupdb"
 
-  find "$tmdest" -maxdepth 1 -mindepth 1 -type d | grep -v "/\." | while read line ; do
+	find "$tmdest" -maxdepth 1 -mindepth 1 -type d | grep -v "/\." | while read -r line; do
 		echo "${line##*/}"
 	done
 }
@@ -26,10 +32,11 @@ function time-machine-list-all-backups() {
 	example "time-machine-list-all-backups my-laptop"
 
 	# Use the local hostname if none provided
-  local COMPUTERNAME=${1:-$(scutil --get ComputerName)}
+	local COMPUTERNAME BACKUP_LOCATION
-  local BACKUP_LOCATION="$(time-machine-destination)/Backups.backupdb/$COMPUTERNAME"
+	COMPUTERNAME=${1:-$(scutil --get ComputerName)}
+	BACKUP_LOCATION="$(time-machine-destination)/Backups.backupdb/$COMPUTERNAME"
 
-  find "$BACKUP_LOCATION" -maxdepth 1 -mindepth 1 -type d | while read line ; do
+	find "$BACKUP_LOCATION" -maxdepth 1 -mindepth 1 -type d | while read -r line; do
 		echo "$line"
 	done
 }
@@ -41,19 +48,22 @@ function time-machine-list-old-backups() {
 	example "time-machine-list-old-backups my-laptop"
 
 	# Use the local hostname if none provided
-  local COMPUTERNAME=${1:-$(scutil --get ComputerName)}
+	local COMPUTERNAME BACKUP_LOCATION
-  local BACKUP_LOCATION="$(time-machine-destination)/Backups.backupdb/$COMPUTERNAME"
+	COMPUTERNAME=${1:-$(scutil --get ComputerName)}
+	BACKUP_LOCATION="$(time-machine-destination)/Backups.backupdb/$COMPUTERNAME"
 
 	# List all but the most recent one
-  find "$BACKUP_LOCATION" -maxdepth 1 -mindepth 1 -type d -name 2\* | sed \$d | while read line ; do
+	find "$BACKUP_LOCATION" -maxdepth 1 -mindepth 1 -type d -name 2\* | sed \$d | while read -r line; do
 		echo "$line"
 	done
 }
 
 # Taken from here: http://stackoverflow.com/a/30547074/1228454
 function _tm_startsudo() {
-    sudo -v
+	sudo -v # validate without running a command.
-    ( while true; do sudo -v; sleep 50; done; ) &
+	(while sudo "-${SUDO_ASKPASS:+A}v"; do
+		sleep 50
+	done) &
 	SUDO_PID="$!"
 	trap _tm_stopsudo SIGINT SIGTERM
 }
@@ -70,15 +80,15 @@ function time-machine-delete-old-backups() {
 	example "time-machine-delete-old-backups my-laptop"
 
 	# Use the local hostname if none provided
-  local COMPUTERNAME=${1:-$(scutil --get ComputerName)}
+	local COMPUTERNAME=${1:-$(scutil --get ComputerName)} _old_backup
 
 	# Ask for sudo credentials only once
 	_tm_startsudo
 
-  echo "$(time-machine-list-old-backups "$COMPUTERNAME")" | while read i ; do
+	while read -r _old_backup; do
 		# Delete the backup
-    sudo tmutil delete "$i"
+		sudo tmutil delete "$_old_backup"
-  done
+	done <<< "$(time-machine-list-old-backups "$COMPUTERNAME")"
 
 	_tm_stopsudo
 }