Android shell script to unmount all external SD card(s)

unmount.md

The script may not work for Android < 6.0.

Simply run unmount.sh in Android terminal to unmount all external SD card(s), partitions formated as internal will be ignored.

To unmount when system starting up, put the script in /data/adb/service.d/ (Magisk root required) and execute chmod +x /data/adb/service.d/unmount.sh. This will be useful if Linux Deploy installs in a SD card partition.

To turn on logs, change LOG_ON=false to LOG_ON=true, the log file will be /data/local/tmp/unmount.log.

unmount.sh

#!/system/bin/sh

LOG_ON=false

LOG_FILE=/dev/null
[ "$LOG_ON" = true ] && LOG_FILE=/data/local/tmp/unmount.log

log() {
  while IFS= read -r; do
    echo "[$(date +%T)] $REPLY" | tee -a "$LOG_FILE"
  done
}

if [ "$(getprop ro.build.version.sdk)" -lt 23 ]; then
  echo "The script may not work for Android < 6.0" | log
  echo "Current version: $(getprop ro.build.version.release)" | log
fi

(
  until [ "$(getprop sys.boot_completed)" -eq 1 ]; do
    echo "Waiting until boot completed..." | log
    sleep 5
  done

  echo "Trying unmounting all public volumes for 5 times anyway..." | log
  for i in $(seq 5); do
    echo "[$i]" | log
    vols=$(sm list-volumes public)
    if [ -z "$vols" ]; then
      echo "No public volumes found." | log
    else
      echo "Public volumes:" | log
      echo "$vols" | log
      echo "$vols" | while IFS= read -r line; do
        vol=$(echo "$line" | cut -d " " -f 1)
        state=$(echo "$line" | cut -d " " -f 2)
        if [ "$state" = unmounted ]; then
          echo "Ignoring unmounted: $vol" | log
          continue
        fi

        echo "Unmounting: $vol" | log
        sm unmount "$vol" 2>&1 | log
        echo "State:" | log
        sm list-volumes public | grep "$vol" | log
      done
    fi
    sleep 5
  done
) &