Rewrite and add more details on attach and nsenter; add bashrc_docker file

_local/bashrc_docker

@@ -0,0 +1,45 @@
+# Some useful commands to use docker.
+# Author: yeasy@github
+# Created:2014-09-25
+
+alias docker-pid="sudo docker inspect --format '{{.State.Pid}}'"
+
+#the implementation refs from https://github.com/jpetazzo/nsenter/blob/master/docker-enter
+function docker-enter() {
+    if [ -e $(dirname "$0")/nsenter ]; then
+        # with boot2docker, nsenter is not in the PATH but it is in the same folder
+        NSENTER=$(dirname "$0")/nsenter
+    else
+        NSENTER=nsenter
+    fi
+    [ -z "$NSENTER" ] && echo "WARN Cannot find nsenter" && return
+
+    if [ -z "$1" ]; then
+        echo "Usage: `basename "$0"` CONTAINER [COMMAND [ARG]...]"
+        echo ""
+        echo "Enters the Docker CONTAINER and executes the specified COMMAND."
+        echo "If COMMAND is not specified, runs an interactive shell in CONTAINER."
+    else
+        PID=$(sudo docker inspect --format "{{.State.Pid}}" "$1")
+        if [ -z "$PID" ]; then
+            echo "WARN Cannot find the given container"
+            return
+        fi
+        shift
+
+        OPTS="--target $PID --mount --uts --ipc --net --pid"
+
+        if [ -z "$1" ]; then
+            # No command given.
+            # Use su to clear all host environment variables except for TERM,
+            # initialize the environment variables HOME, SHELL, USER, LOGNAME, PATH,
+            # and start a login shell.
+            #sudo $NSENTER "$OPTS" su - root
+            sudo $NSENTER --target $PID --mount --uts --ipc --net --pid su - root
+        else
+            # Use env to clear all host environment variables.
+            sudo $NSENTER --target $PID --mount --uts --ipc --net --pid env -i $@
+        fi
+    fi
+}
+