A really stupid entrypoint script from the mongo docker container version 3.2.3

mongo-entrypoint.sh

#!/bin/bash
set -e
 
# if parameters that start with '-' were passed to the script via the CMD directive then concat
# them to the string 'mongod'
if [ "${1:0:1}" = '-' ]; then
        set -- mongod "$@"
fi
 
# if the last conditional statement was triggered or if we're running without any parameters
# (ie, the parameter 'mongod' was passed in from  +++the docker executor) AND we're running as
# root then do stuff.  NOTE: if we're inside of recursion this won't fire 
if [ "$1" = 'mongod' -a "$(id -u)" = '0' ]; then
        # give the mongodb user ownership of its working dirs
        chown -R mongodb /data/configdb /data/db
        # recurse into this script but run as the user mongodb (bash_source is a shortcut to
        # the name of the script we're currently in)
        # gosu is an off-brand su command. ex: gosu <username> <executable> <arguments>
        exec gosu mongodb "$BASH_SOURCE" "$@"
fi
 
# this is the final step where we preface the $@ string with numactl which handles memory 
# usage. This will execute every time unless the parameters sent are something other than mongod or an argument.
if [ "$1" = 'mongod' ]; then 
        numa='numactl --interleave=all'
        if $numa true &> /dev/null; then
                set -- $numa "$@"
        fi  
fi
 
#here we actually fire off whatever is in the $@ string.
exec "$@"