Sometimes I need access to my 1Password database on another computer. This launchd task will automatically copy my database to a USB drive as soon as it's changed.

backup_passwords.sh

#!/bin/sh
if ! [ -d "/Volumes/RECOVERY" ]; then
  echo "Not connected"
  exit 1
fi

mkdir -p "/Volumes/RECOVERY/passwords"
rsync -az --delete --exclude ".DS_Store" \
  "/Users/penman/dropbox/Apps/1Password/1Password.agilekeychain" \
  "/Volumes/RECOVERY/passwords"

com.rosspenman.backuppasswords.plist

<?xml version="1.0" encoding="UTF-8"?>
<!DOCTYPE plist PUBLIC "-//Apple//DTD PLIST 1.0//EN" "http://www.apple.com/DTDs/PropertyList-1.0.dtd">
<plist version="1.0">
  <dict>
    <key>Label</key>
    <string>com.rosspenman.backuppasswords</string>
    <key>Program</key>
    <string>/Users/penman/bin/backup_passwords</string>
    <key>StartOnMount</key>
    <true/>
    <key>WatchPaths</key>
    <array>
      <string>/Users/penman/dropbox/Apps/1Password/1Password.agilekeychain</string>
    </array>
  </dict>
</plist>