#!/bin/bash

# A script which substitutes recursively the content of the files of a folder
# with their own sha1sum
# http://perassi.org/2008/01/03/hashem-all/
# 2008-01-03

# It was written by Carlo Perassi <carlo@perassi.org> as a modified version
# of Kaz Kylheku script

# From: kaz@ashi.footprints.net (Kaz Kylheku)
# Newsgroups: comp.os.linux.misc
# Subject: Re: bash question: subdirectories
# Message-ID: <slrn8a0gu9.v5n.kaz@ashi.FootPrints.net>
# Date: Tue, 08 Feb 2000 16:24:35 GMT

# Actually it can be made to. That is to say, it is possible to code a recursive
# descender function in the bash language. Here is an example.
#
# What is nice about this is that you can embed the function into your shell
# script. The function changes the current working directory as it descends.
# So it can handle arbitrarily deep paths. Whereas paths generated by the
# find command can cause a problem when they get too long; the kernel has a
# hard limit on the length of the string passed to the open() and other
# system calls.

# There are races; what if the directory tree is blown away during the traversal?
# The function won't be able to crawl back up using the .. link and will just
# bail.

# Recursive Directory Traverser
# Author: Kaz Kylheku
# Date: Feb 27, 1999
# Copyright 1999

# Function parameter usage:
# $1 directory to process

function recurse
{
    local file
    local path

    path="${1%/}/"

    if cd "$1" ; then
        for file in $(ls -la); do
            if [ -f "$file" ]; then
                sha1sum $file | sponge $file
            fi
        done
        for file in .* * ; do
            if [ "$file" = "." ] || [ "$file" = ".." ] ; then
                continue
            fi
            if [ -d "$file" ] && [ ! -L "$file" ]; then
                recurse $file "$(ls -la)"
            fi
        done
        cd ..
    fi
}

if [ $# -eq 0 ]
then
  echo "Invoke with a folder name as first argument"
  exit
fi
recurse $1