[Tutor] .tar.gz in Py (was: do pythons like coffee?)

[Nick Lunt]

Hi Andrei,

I asked a tar question myself yesterday and included my problematic program. Here it is -

# CODE

"""
tar.py:
Usage: 
        tar.py filetocreate.tar list_of_files_to_tar

imports:
        tarfile -        to do the tarring
        sys -            to manipulate command line args        
"""

# Fails in the if block on os.access when dirs are submitted as args.
# ie the dir submitted is readable but some files below it may not be,
# which the if os.access() does not pick up.
# So create a new function to walk the dir and only return the files it can
# backup successfully, but print a list of the ones it cant.


import tarfile, sys, os

if len(sys.argv) <= 2:
        print 'Error:', sys.argv[0], ' <tarfile.tar> <list of files to tar>'
        sys.exit(1)

tfile = sys.argv[1]

totar = []
for f in sys.argv[2:]:
        if os.access(f, os.R_OK):
                totar.append(f)
        else:
                print 'Could not access', f, 'to tar'


tf = tarfile.TarFile(tfile, 'w')
for f in totar:
        tf.add(f)

tf.close()

# END CODE

As you can see from the comments in my code it is not perfect yet, but it will hopefully show you how to use the tar module, and it will create a tar file for you.

There is also a gzip module you can import to gzip the tar file, but I've not got my head round that yet as the tar part is not 100%, but that is my plans for it. Then it's going to write it to CD. Then I'd like to make a GUI for it, just to learn how to ;) Oh yeah, the final version is also gonna be OOP.

Hope that helps a bit,
Cheers
Nick.



On Sat, 31 Jan 2004 22:29:18 +0100
Andrei <project5 at redrival.net> wrote:

> Hi,
> 
> I have a batch file in which I create a tar.gz file of a directory
> containing nested subdirectories (and files) using the 7-zip command line,
> like this:
> 
> 7z.exe a -ttar ..\myfile.tar * -r
> cd..
> 7z.exe a -tgzip myfile.tar.gz myfile.tar -r
> 
> The result then looks somewhat like this:
> 
>   - myfile.tar.gz
>        |
>        |- myfile.tar
>              |
>              |- file1.ext
>              |- dir1
>                    |
>                    |-file2.ext
> 
> Python has a tarfile module so I was thinking I'd like to migrate that to
> Python (not just by running os.system()) because I use it in building a
> distro for a program. The problem is that the docs for the tarfile module
> don't seem to fit my brain and I also can't find any decent sample code. 
> Does anyone know any examples for using the tarfile module?
> 
> -- 
> Yours,
> 
> Andrei
> 
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