Merge pull request #9 from rbberger/remove_sha1sum_dependency

# Makefile for LAMMPS documentation

SHA1          = $(shell echo $USER-$PWD | sha1sum | cut -f1 -d" ")

SHA1          = $(shell echo $USER-$PWD | python utils/sha1sum.py)

BUILDDIR      = /tmp/lammps-docs-$(SHA1)

RSTDIR        = $(BUILDDIR)/rst

VENV          = $(BUILDDIR)/docenv

## Installing prerequisites

To run the documention build toolchain Python 3 and virtualenv have to be

installed. The following are instructions for common Linux distributions:

installed. Here are instructions for common setups:

### virtualenv

#### Ubuntu

### Ubuntu

```bash

sudo apt-get install python-virtualenv

```

#### Fedora

### Fedora

```

sudo yum install python-virtualenv

```

### MacOS X

## Python 3

Download the latest Python 3 MacOS X package from https://www.python.org and install it.

This will install both Python 3 and pip3.

## virtualenv

Once Python 3 is installed, open a Terminal and type `pip3 install virtualenv`. This will

install virtualenv from the Python Package Index.

#!/bin/env python

# simple utility which reimplements sha1sum using Python

import hashlib

import sys

s = hashlib.sha1()

s.update(sys.stdin.read().encode())

print(s.hexdigest())