MacOS -> {username} -> Library -> LaunchAgents

local.nas.backup-documents.plist

<!--
  Backup files in the `Documents` folder to the NAS.
  @see https://www.launchd.info/
  @see https://www.cis.upenn.edu/~bcpierce/unison/download/releases/stable/unison-manual.html
  @see https://linux.developpez.com/unison/
  @see http://xahlee.info/UnixResource_dir/unison_file_sync.html
  @see https://superuser.com/questions/1272832/how-do-i-ignore-folders-and-its-subdirectories-in-unison-sync
  @see https://superuser.com/questions/1166185/making-unison-ignore-file-property-differences
-->
<?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>local.nas.backup-documents</string>
  <key>RunAtLoad</key>
  <false/>
  <key>StartOnMount</key>
  <true/>
  <key>KeepAlive</key>
  <false/>
  <key>StartInterval</key>
  <integer>1200</integer>
  <key>ProgramArguments</key>
  <array>
    <string>/usr/local/bin/unison</string>
    <string>/Users/{username}/Documents/</string>
    <string>/Volumes/{folder_name}</string>
    <string>-auto</string>
    <string>-batch</string>
    <string>-fastcheck=true</string>
    <string>-perms=0</string>
    <string>-dontchmod=true</string>
    <string>-times=true</string>
    <string>-log=false</string>
    <string>-retry=3</string>
    <string>-ignore=Name .DS_Store</string>
    <string>-ignore=Name .tscache</string>
    <string>-ignore=Name .git</string>
    <string>-ignore=Name vendor</string>
    <string>-ignore=Name platforms</string>
    <string>-ignore=Name node_modules</string>
  </array>
  <key>StandardErrorPath</key>
  <string>/Users/{username}/local.nas.backup-documents.stderr</string>
  <!--<key>StandardOutPath</key>
  <string>/Users/{username}/local.nas.backup-documents.stdout</string>-->
</dict>
</plist>