get_disk_usage

#!/bin/sh

if [ $# != 0 ]; then
  df -P $@
  exit 0
fi

IsInContainer=false

CGROUP=/proc/1/cgroup
SCHED=/proc/1/sched
DOCKERENV=/.dockerenv

if [ -f "$CGROUP" ]; then
  if grep /docker/ $CGROUP -qa; then
    IsInContainer=true
  elif grep /lxc/ $CGROUP -qa; then
    IsInContainer=true
  fi
elif [ -f "$SCHED" ]; then
  if cat $SCHED | head -n 1 | grep -vqa "(1,"; then
    IsInContainer=true
  fi
elif [ -f "$DOCKERENV" ]; then
  IsInContainer=true
fi

if [ "$IsInContainer" = "true" ]; then
  df -P /
else
  df -P
fi