Re: [gentoo-user] Writing a bash script or thinking about it anyway.

[Francisco Ares]

On Tue, Dec 22, 2009 at 3:09 AM, Dale <rdalek1967@×××××.com> wrote:
> Neil Walker wrote:
>>
>> Dale wrote:
>>
>>>
>>> Me again.  I'm thinking about writing a bash script that backs up my
>>> /home directory.
>>>
>>
>> I use a simple rsync cron job to backup entire servers every hour. Does
>> the job for me. ;)
>>
>>
>> Be lucky,
>>
>> Neil
>> http://www.the-workathome.com
>>
>>
>
> But I wouldn't learn how to write a script that way.  I got to start
> somewhere.  This is a good place.
>
> Dale
>
> :-)  :-)
>

Now I got your point.

I would think on something like this (untested):


The command line would be

BackupScriptName  FromDirectory  ToDirectory


#! /bin/bash
FROM=$1
TO=$2
cd $FROM
for i in * .??*
do
    if [[ -d "$i" ]]   # is it a directory?
    then
        # yes, it is a directory
        if [[ -e "$TO/$i" ]] && [[ -d "$TO/$i" ]]
        then

        # on the TO side, the name exists
        # and it is a directory
            cd "$i"

            # just to show something
            pwd

            # calls recursively this same script
            $0 "$FROM/$i" "$TO/$i"
            cd ..

        else
            # didn't existed yet on the TO side,
            # so copy everything
            cp -a $FROM/$i $TO/$i
        fi
    else
        # it is a file, not a directory
        if [[ -e "$TO/$i" ]]
        then
            # the file already exists

            # do something to compare the files, like:

            # gets size from "ls" result
            SIZE1=`ls -l "$i" | cut -d" " -f5`
            SIZE2=`ls -l "TO/$i" | cut -d" " -f5

            if (( $SIZE1!=$SIZE2 ))
            then

                # size is different, so copy the file
                cp -a "$FROM/$i" "$TO/$i"

            else
                # more tests for differences other
                # than size, like date/time
                # or even MD5SUM
            fi
        else

            # file doesn't exist at the "TO" side
            cp -a "$FROM/$i" "$TO/$i"

        fi

    fi

done


Hope this helps
Francisco
-- 
"If you have an apple and I have an apple and we exchange apples then
you and I will still each have one apple. But if you have an idea and
I have one idea and we exchange these ideas, then each of us will have
two ideas." - George Bernard Shaw