OSX mount user smb or nfs mountpoint when wifi present, avoid OSX Catalina automount repeated mountpoints issues

com.userdomain.mountpoint.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>Enabled</key>
	<true/>
	<key>Label</key>
	<string>com.userdomain.mountpoint</string>
	<key>ProgramArguments</key>
	<array>
		<string>/bin/sh</string>
		<string>/Users/username/bin/mount_wifi_smb_example.sh</string>
	</array>
	<key>RunAtLoad</key>
	<true/>
	<key>StartInterval</key>
	<integer>300</integer>
</dict>
</plist>

mount_wifi_nfs_example.sh

#!/bin/bash
if [ -f '/Volumes/mountpoint/.mounted' ]; then
   #echo Nothing to do, share is mounted
   exit
else
   if [ -z `/Users/username/bin/airport -I | grep '.* SSID:' | sed 's/^.* SSID: //'` ]; then
      #echo SSID is Null, we're not connected with the Airport to any Network.
      umount -f /Volumes/mountpoint
      rmdir /Volumes/mountpoint
      exit
   else 
      if [ ! -d '/Volumes/mountpoint' ]; then
         mkdir '/Volumes/mountpoint'
      fi
      if [ `/Users/username/bin/airport -I | grep '.* SSID:' | sed 's/^.* SSID: //'` == "wifiname" ]; then
         #echo SSID is wifiname!
         /sbin/mount -o rw,locallocks,noowners,nolockd,resvport,rsize=65536,wsize=65536,intr,hard,tcp,rdirplus,readahead=128,nfc -t nfs '//machine/mnt/mountpoint' '/Volumes/mountpoint'
         touch /Volumes/mountpoint/.mounted

      elif [ `/Users/username/bin/airport -I | grep '.* SSID:' | sed 's/^.* SSID: //'` == "wifiname2" ]; then
         #echo SSID is wifiname2!
         /sbin/mount -o rw,locallocks,noowners,nolockd,resvport,rsize=65536,wsize=65536,intr,hard,tcp,rdirplus,readahead=128,nfc -t nfs '//machine/mnt/mountpoint' '/Volumes/mountpoint'
         touch /Volumes/mountpoint/.mounted

      fi
   fi
fi

mount_wifi_smb_example.sh

#!/bin/bash
if [ -f '/Volumes/mountpoint/.mounted' ]; then
   #echo Nothing to do, share is mounted
   exit
else
   if [ -z `/Users/username/bin/airport -I | grep '.* SSID:' | sed 's/^.* SSID: //'` ]; then
      #echo SSID is Null, we're not connected with the Airport to any Network.
      umount -f /Volumes/mountpoint
      rmdir /Volumes/mountpoint
      exit
   else 
      if [ ! -d '/Volumes/mountpoint' ]; then
         mkdir '/Volumes/mountpoint'
      fi
      if [ `/Users/username/bin/airport -I | grep '.* SSID:' | sed 's/^.* SSID: //'` == "wifiname" ]; then
         #echo SSID is wifiname!
         /sbin/mount -o nodev,nosuid -t smbfs '//username:smbpasswd@machine/mountpoint' '/Volumes/mountpoint'
         touch /Volumes/mountpoint/.mounted

      elif [ `/Users/username/bin/airport -I | grep '.* SSID:' | sed 's/^.* SSID: //'` == "wifiname2" ]; then
         #echo SSID is wifiname2!
         /sbin/mount -o nodev,nosuid -t smbfs '//username:smbpasswd@machine/mountpoint' '/Volumes/mountpoint'
         touch /Volumes/mountpoint/.mounted

      fi
   fi
fi

This assumes you have the 'airport' binary utility present in your home directory. I copied it there a long time ago, but here is at least one reference to how the user getting access to it easily.

http://osxdaily.com/2007/01/18/airport-the-little-known-command-line-wireless-utility/

Correct if statement for testing existence of the .mounted file is to use '-f' instead of '-d' which was for directory previously checking that instead of contained .mounted file. The file prevents detecting the same path exists but is a local directory instead of the mountpoint.