a shell script for enter a container (using nsenter)

docker-enter

#!/bin/sh
# a shell script for enter a container (using nsenter)
bin=$(which nsenter)
if [ -z "$bin" ] ; then
  echo "please get nsenter using ( docker run --rm -v /usr/local/bin:/target jpetazzo/nsenter  ) \n  from  https://github.com/jpetazzo/nsenter "
  exit 1
fi

c="";
if [ -z "$1" ] ; then
  docker ps | awk '{ print NR-1,$0 } '
  echo "please input docker the container id or number (default is first one) :"
  read c;
else
 c=$1;
fi
if [ -z "$c" ] ; then
  c=1;
fi
 if expr $c + 0 > /dev/null 2>&1 ; then
   c=$( docker ps | awk "NR-1==$c { print \$1; exit }" )
 fi
 PID=$(docker inspect --format {{.State.Pid}} $c)
 if [ -n "$PID" ] ; then
   docker ps | grep $c 
   echo "press any to enter the container($c,PID=$PID)"
   read ok;
   if [ "Y"  = "Y" ] ; then
     nsenter bash  --target $PID --mount --uts --ipc --net --pid
   fi
 else
   echo "can not found the pid for  container :$c !"
 fi

example:

curl  --remote-name https://gist.githubusercontent.com/qxo/9263b69f2e04f347de96/raw/a007d87e8e96423694b3782dfa988fd96c7b0d86/docker-enter 
chmod +x ./docker-enter
./docker-enter