awk file redirect issue

sumathi_subramaniam · 11-04-2013, 06:56 AM

We have an issue with awk in linux.
We have a ${file2} present in a directory. When following command is executed ,it is creating overlapping files.

awk -F'|' '$22 <= 20131101 { print $0 }' ${file1} > ${file2}

Over lap file:
some content from $file1
some content from existing ${file2}

druuna · 11-04-2013, 07:04 AM

Can you be a bit more specific about your problem?

If I look at the above code, there doesn't seem to be anything wrong with it. A single > is used, so no appending is done.

${file1} holds the name of the input file, ${file2} holds the name of the output file. Have you checked the correctness of the actual file names?

sumathi_subramaniam · 11-04-2013, 07:14 AM

But somehow appending is done even though only > is used . Not just clean appending ,it creates overlapped file.
File names looks good to me

druuna · 11-04-2013, 07:22 AM

I just did the following test and I cannot reproduce your problem:

Code:

$ file1=input
$ file2=output
$ ls- l ${file1} ${file2}
ls: cannot access output: No such file or directory
-rw-r----- 1 druuna druuna 95 nov  4 14:19 input
$ cat ${file1}
1|2|3|20131030|5|6
1|2|3|20131031|5|6
1|2|3|20131101|5|6
1|2|3|20131102|5|6
1|2|3|20131103|5|6
$ awk -F'|' '$4 <= 20131101 { print $0 }' ${file1}  > ${file2}
$ cat ${file2}
1|2|3|20131030|5|6
1|2|3|20131031|5|6
1|2|3|20131101|5|6
$ awk -F'|' '$4 <= 20131101 { print $0 }' ${file1}  > ${file2}
$ cat ${file2}
1|2|3|20131030|5|6
1|2|3|20131031|5|6
1|2|3|20131101|5|6

Can you post a relevant part of the input and the resulting output?

sumathi_subramaniam · 11-04-2013, 07:31 AM

Me too unable to replicate outside the script.
This command is executed as a part of batch process,where ${file2} was previously created by first instances of the script.
When the second instance tries to overwrite the ${file2},it is getting corrupted

druuna · 11-04-2013, 07:39 AM

Quote:

Originally Posted by sumathi_subramaniam

Me too unable to replicate outside the script.
This command is executed as a part of batch process,where ${file2} was previously created by first instances of the script.
When the second instance tries to overwrite the ${file2},it is getting corrupted

If that is the case then the problem is not awk but something else in the script(s).

Without knowing how the script(s) is/are implemented and what code they contain it is impossible to help you.

pan64 · 11-04-2013, 07:39 AM

probably several scripts run in the same time and that causes corruption?