Re: [Help-tar] Trouble with tar -xzf when using --files-from=-

[Reuti]

> Am 21.10.2015 um 12:32 schrieb Reuti <address@hidden>:
> 
> Hi,
> 
> 
>> Am 21.10.2015 um 03:20 schrieb Tony Olekshy <address@hidden>:
>> 
>> Hello.
>> 
>> I'm having trouble understanding why I can't pipe the output of a
>> tar -tzf a.tgz ... through to a tar -xzf a.tgz --files=from=- ...
>> without producing what appear to be spurious messages. In practice
>> I want to place a filter in that pipeline to select just what to
>> extract, but the following script simplifies that out to just show
>> the problem I'm encountering.
> 
> Accessing "." in the archive will move its pointer already to the end:
> 
> $ echo . | tar tf archive.tgz --files-from=-
> ./
> ./foo/
> ./foo/bar

Ah, although I missed the --no-recursion at the first glance: its position is 
important. It must appear before the --files-from=- in your case.

Nevertheless I wonder: --no-recursion is listed under "local file selection", 
it's behavior during extraction sounds like --exact-match as there are plain 
files in an archive I would say, not directories.

-- Reuti


> BTW: there is the option -C to easy to write to any directory with `tar`.
> 
> -- Reuti
> 
> 
>> Here are my test script and my questions thereto. Any insight you
>> can provide me with would be appreciated.
>> 
>> #!/bin/bash
>> #-----------------------------------------------------------------------
>> #
>> #   Subject: Trouble with tar -xzf when using --files-from=-
>> #
>> #   From Tony Olekshy, Avra Software Lab Inc., 2015-10-20.
>> #
>> #   The following has been reproduced with the GNU tar 1.26 that came
>> #   with Fedora release 18, with GNU tar 1.27.1 and 1.28 which I just
>> #   compiled on Fedora release 18, and with the GNU tar 1.23 that came
>> #   with Red Hat Enterprise Linux Server release 6.6.
>> #
>> #   Step 5 below produces these messages:
>> #
>> #       tar: ./foo: Not found in archive
>> #       tar: ./foo/bar: Not found in archive
>> #       tar: Exiting with failure status due to previous errors
>> #
>> #   But step 6 shows that ./foo & ./foo/bar were in fact correctly
>> #   extracted into $TEST/into, so they were found in the archive!
>> #
>> #   My questions are: Why does step 5 produce those messages?
>> #   What am I misunderstanding, or is there some bug in tar?
>> #
>> set -v #----------------------------------------------------------------
>> 
>> : Step 1: Create the testing environment...
>> :
>> export TAR=/bin/tar TEST=~/test
>> 
>> echo; $TAR --version | grep 'GNU tar'
>> 
>> mkdir -p $TEST/from/foo $TEST/into
>> rm -rf $TEST/archive.tgz $TEST/into/*
>> date > $TEST/from/foo/bar
>> 
>> : Step 2: Show the contents of $TEST...
>> :
>> echo; cd $TEST; find . | sort | xargs ls -ld
>> 
>> : Step 3: Create $TEST/archive.tgz...
>> :
>> cd $TEST/from; find .   \
>>                       \
>>   | $TAR -vczf $TEST/archive.tgz --files-from=- --no-recursion
>> 
>> : Step 4: Show the contents of archive.tgz...
>> :
>> cd $TEST; $TAR -tzf $TEST/archive.tgz
>> 
>> : Step 5: Extract files from archive.tgz using --files-from...
>> :
>> cd $TEST; $TAR -tzf $TEST/archive.tgz | ( cd $TEST/into;
>> 
>>   $TAR -vxzf $TEST/archive.tgz --files-from=- --no-recursion )
>> 
>> : Step 6: Show the contents of $TEST...
>> :
>> echo; cd $TEST; find . | sort | xargs ls -ld
>> 
>> exit #------------------------------------------------------------------
>> 
>> Here is the output from running that script...
>> 
>> : Step 1: Create the testing environment...
>> :
>> export TAR=/bin/tar TEST=~/test
>> 
>> echo; $TAR --version | grep 'GNU tar'
>> 
>> tar (GNU tar) 1.26
>> 
>> mkdir -p $TEST/from/foo $TEST/into
>> rm -rf $TEST/archive.tgz $TEST/into/*
>> date > $TEST/from/foo/bar
>> 
>> : Step 2: Show the contents of $TEST...
>> :
>> echo; cd $TEST; find . | sort | xargs ls -ld
>> 
>> drwxr-x--- 4 olekshy olekshy 4096 Oct 20 18:52 ./
>> drwxr-x--- 3 olekshy olekshy 4096 Oct 20 18:37 ./from/
>> drwxr-x--- 2 olekshy olekshy 4096 Oct 20 18:37 ./from/foo/
>> -rw-r----- 1 olekshy olekshy   29 Oct 20 18:52 ./from/foo/bar
>> drwxr-x--- 2 olekshy olekshy 4096 Oct 20 18:52 ./into/
>> 
>> : Step 3: Create $TEST/archive.tgz...
>> :
>> cd $TEST/from; find .   \
>>                       \
>>   | $TAR -vczf $TEST/archive.tgz --files-from=- --no-recursion
>> ./
>> ./foo/
>> ./foo/bar
>> 
>> : Step 4: Show the contents of archive.tgz...
>> :
>> cd $TEST; $TAR -tzf $TEST/archive.tgz
>> ./
>> ./foo/
>> ./foo/bar
>> 
>> : Step 5: Extract files from archive.tgz using --files-from...
>> :
>> cd $TEST; $TAR -tzf $TEST/archive.tgz | ( cd $TEST/into;
>> 
>>   $TAR -vxzf $TEST/archive.tgz --files-from=- --no-recursion )
>> ./
>> ./foo/
>> ./foo/bar
>> /bin/tar: ./foo: Not found in archive
>> /bin/tar: ./foo/bar: Not found in archive
>> /bin/tar: Exiting with failure status due to previous errors
>> 
>> : Step 6: Show the contents of $TEST...
>> :
>> echo; cd $TEST; find . | sort | xargs ls -ld
>> 
>> drwxr-x--- 4 olekshy olekshy 4096 Oct 20 18:52 ./
>> -rw-r----- 1 olekshy olekshy  195 Oct 20 18:52 ./archive.tgz
>> drwxr-x--- 3 olekshy olekshy 4096 Oct 20 18:37 ./from/
>> drwxr-x--- 2 olekshy olekshy 4096 Oct 20 18:37 ./from/foo/
>> -rw-r----- 1 olekshy olekshy   29 Oct 20 18:52 ./from/foo/bar
>> drwxr-x--- 3 olekshy olekshy 4096 Oct 20 18:37 ./into/
>> drwxr-x--- 2 olekshy olekshy 4096 Oct 20 18:37 ./into/foo/
>> -rw-r----- 1 olekshy olekshy   29 Oct 20 18:52 ./into/foo/bar
>> 
>> exit #------------------------------------------------------------------
>> 
>> Sincerely Yours,
>> Tony Olekshy
>> Avra Software Lab Inc.
>> 
>