tar: file changed as we read it

Question

I am using `make` and `tar` to backup. When executing makefile, tar command shows `file changed as we read it`. In this case, - the tar package is ok when the warning comes up - but it stops the tar command for the following backup - the file showing the warning in fact doesn't change -- it is really strange that the warning comes up - the files showing the warning come up randomly, I mean, everytime I run my makefile, the files showing the warning are different - `--ignore-failed-read` doesn't help. I am using tar 1.23 in MinGW - I just changed my computer to WIN7 64 bit. The script works well in old WIN7 32 bit. But the tar version is not as new as the 1.23. How can I stop the tar's warning to stop my backup following the warning? Edit-2: it might be the reason As I said above, the bash shell script worked well in my old computer. Comparing with the old computer, the `msys` version is different. So is the version of tar command. In the old computer, tar is 1.13.19 and it is 1.23 in…

Accepted Answer

I also encounter the tar messages "changed as we read it". For me these message occurred when I was making tar file of Linux file system in bitbake build environment. This error was sporadic.

For me this was not due to creating tar file from the same directory. I am assuming there is actually some file overwritten or changed during tar file creation.

The message is a warning and it still creates the tar file. We can still suppress these warning message by setting option

`--warning=no-file-changed`

(http://www.gnu.org/software/tar/manual/html_section/warnings.html )

Still the exit code return by the tar is "1" in warning message case: http://www.gnu.org/software/tar/manual/html_section/Synopsis.html

So if we are calling the tar file from some function in scripts, we can handle the exit code something like this:

```
set +e 
tar -czf sample.tar.gz dir1 dir2
exitcode=$?

if [ "$exitcode" != "1" ] && [ "$exitcode" != "0" ]; then
    exit $exitcode
fi
set -e
```

tar: file changed as we read it

Solution

Problem