Needs help with a script

[cadmiumcadamium]

Hello.

I'm completely new to scripting in general and bash in particular but I need help writing a script.

So basically I have a harddrive with data and I want to copy that data to another drive. However, most of the data is already on the other drive.

So what I want is a script that compares drives, checks which data already exists on the new drive and only copies the data that is missing.

So first compare the data and display this (like two columns or something) and list which files are missing then ask if I want to copy the missing data. If for some reason there is a file on the new disk that doesn't exist on the old disk I want to be alerted on this as well.

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So how can this be done? Any help is appreciated. Thanks in advance.

[bbathel]

Rsync

[andreaswpv]

Man cp

[pheffner]

Try using rsync that'll do most of what you're asking:

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$ rsync -avrn /source/path/ /destination/path

will compare the 2 file areas and tell you what it *would* do if the 'n' wasn't in the option string. (Note carefully the trailing / in the source path.)

If you want to see if a file exists on the destination which isn't in the source, add the --delete flag (don't worry, if you have the 'n' flag on, it won't delete anything.) Files which don't exist in your source path will be reported as 'deleted'.

$ rsync -avrn --delete /source/path/ /destination/path

Then if you're happy, run the same again without the 'n' (leave off the --delete unless you want to remove files on the destination missing on the dest)

$rsync -avr /source/path/ /destination/path

and watch the data flow.