Example launchd plist file and shell script etc. for debugging the environment when running scripts as a user.

commands

# How to get running and monitor

chmod 777 /Users/username/bin/debug.sh
launchd unload -w /Library/LaunchDaemons/debug.plist
launchd load -w /Library/LaunchDaemons/debug.plist

tail -f /Users/username/tmp/debug.stderr.log
tail -f /Users/username/tmp/debug.stdout.log

debug.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>debug</string><!-- this one should match the file name, sans .plist -->
  <key>ProgramArguments</key>
  <array>
    <string>/Users/username/bin/debug.sh</string><!-- good idea if this is similar to the Label -->
  </array>
  <key>StartInterval</key>
  <integer>15</integer>
  <key>StandardOutPath</key>
  <string>/Users/username/tmp/debug.stdout.log</string>
  <key>StandardErrorPath</key>
  <string>/Users/username/tmp/debug.stderr.log</string>
  <key>AbandonProcessGroup</key>
  <true/>
</dict>
</plist>

debug.sh

#!/bin/sh

# Check what environment variables are already set
echo $PATH

# Amend, or set as needed:
#PATH=/usr/local/bin:$PATH

# Executables:
which ruby
ruby -v

# Gems/libraries:
gem list

# Now you'll know more before trying to run something like this:
#RAILS_ENV=production
#rake my:custom:task