Avoid programmer error

Use 'find "$VAR" | xarg rm -fr' which will error out if $VAR is unset.

2 files changed, 10 insertions, 7 deletions

diff --git a/src/rc.slack-autoupdate b/src/rc.slack-autoupdate
index 9563388..ba5f847 100644
--- a/src/rc.slack-autoupdate
+++ b/src/rc.slack-autoupdate
@@ -1,6 +1,6 @@
 #!/bin/bash 
 #
-# Automatically update your system on reboot using packages in the UPDATE_DIR.
+# Automatically update your system on reboot using packages in the PACKAGE_DIR.
 #
 # Sometimes there are additional steps to make when your kernel is updated.
 # You can define these in a custom 'install-kernel' command which this script
@@ -11,9 +11,9 @@ export PATH=$PATH:/usr/local/bin:/usr/local/sbin
 
 # Where packages are stored pending installation.  You can use sub-directories
 # to order and group packages.
-UPDATE_DIR="/var/spool/slack-autoupdate"
+PACKAGE_DIR="/var/spool/slack-autoupdate"
 
-UPDATES="$(find "$UPDATE_DIR" -name '*.t*z' | sort)"
+UPDATES="$(find "$PACKAGE_DIR" -name '*.t*z' | sort)"
 
 if [ -z "$UPDATES" ]; then
   exit 0
@@ -37,6 +37,8 @@ if [ "$OLD_KERNEL" != "$NEW_KERNEL" ]; then
 fi
 
 # All package updates have been processed.
-find "$UPDATE_DIR" -mindepth 1 | xargs rm -fr
+#
+# This will error out if PACKAGE_DIR is accidentally unset.
+find "$PACKAGE_DIR" -mindepth 1 | xargs rm -fr
 
 reboot
diff --git a/src/slack-autoupdate b/src/slack-autoupdate
index 4a7a80f..78501a8 100644
--- a/src/slack-autoupdate
+++ b/src/slack-autoupdate
@@ -19,7 +19,8 @@ NOTIFY="${NOTIFY:-no}"
 # Set to empty to disable reboot or 'now' to reboot immediately.
 REBOOT_TIME="${REBOOT_TIME:-""}"
 
-# Packages are copied here on successful download.
+# Packages are copied here on successful download.  All contents of this
+# directory will be deleted.
 PACKAGE_DIR="${PACKAGE_DIR:-/var/spool/slack-autoupdate}"
 
 # Packages are temporarily stored here until success.  All contents of this
@@ -54,8 +55,8 @@ fi
 
 # Make the set of package updates available atomically by storing them in a
 # temporary location until completion. 
-rm -fr "$STAGING_DIR"
 mkdir --parents "$STAGING_DIR"
+find "$STAGING_DIR" -mindepth 1 | xargs rm -fr
 
 if ! OUTPUT="$(
   # Capture this subshell's error output to standard output.
@@ -219,8 +220,8 @@ if [ -f "$UPDATE_ERROR" ]; then
 fi
 
 # Now that everything is successful.
+find "$PACKAGE_DIR" -mindepth 1 | xargs rm -fr
 mv "$STAGING_DIR"/* "$PACKAGE_DIR/"
-rm -fr "$STAGING_DIR"
 
 if [ -n "$REBOOT_TIME" ]; then
   nohup shutdown -r "$REBOOT_TIME" >/dev/null 2>&1 &