Checking parameters and showing help

.dockerignore

@@ -1,2 +1 @@
 .git
-.README.md

Dockerfile

@@ -1,7 +1,6 @@
 FROM debian:wheezy
 MAINTAINER Adrian Dvergsdal [atmoz.net]
 
-# Install OpenSSH
 RUN apt-get update && \
     DEBIAN_FRONTEND=noninteractive apt-get -y install openssh-server && \
     rm -rf /var/lib/apt/lists/*
@@ -9,9 +8,9 @@ RUN apt-get update && \
 # sshd needs this directory to run
 RUN mkdir -p /var/run/sshd
 
-# Copy configuration and entrypoint script
 COPY sshd_config /etc/ssh/sshd_config
 COPY entrypoint /
+COPY README.md /
 
 EXPOSE 22
 

entrypoint

@@ -1,10 +1,26 @@
 #!/bin/bash
 
+if [ $1 == "--readme" ]; then
+    cat /README.md
+    exit 0
+fi
+
+if [[ -z $1 || $1 =~ ^--help$|^-h$ ]]; then
+    echo "Syntax: user:pass[:e][:[uid][:gid]]..."
+    echo "Use --readme for information and examples."
+    exit 0
+fi
+
 for users in "$@"; do
     IFS=':' read -a data <<< "$users"
     user="${data[0]}"
     pass="${data[1]}"
 
+    if [ -z "$user" -o -z "$pass" ]; then
+        echo "You must at least provide a username and a password."
+        exit 1
+    fi
+
     if [ "${data[2]}" == "e" ]; then
         chpasswdOptions="-e"
         uid="${data[3]}"