Re: delete columns csv file

On 4/3/2008 9:38 PM, r wrote:
> 
> Ed Morton wrote:
> 
> 
>>On 4/3/2008 8:27 PM, r wrote:
>>
>>>Cesar Rabak wrote:
>>>
>>>
>>>
>>>>$awk -F, -f file.awk file2.csv
>>>
>>>
>>>I followed your instructions, also repeating with absolute file name
>>>paths, no syntax error but the cursor returned to the next line, no
>>>response from command terminal. I looked at the file using a text
>>>editor; no changes to content. What next should I check?
>>
>>As I said, you need to parse the file twice:
>>
>>	awk -F, -f file.awk file2.csv file2.csv
>>
>>Regards,
>>
>>	Ed.
> 
> 
> Thank you, I forgot. Success! The command terminal shows the suitably
> amended data. I tried to pipe the command to gedit but all I got was a
> blank new file. So, how do I either send the command terminal display
> output to a program such as gnumeric and save as a new file?

Those are OS-specific questions, not awk questions but if you're on UNIX
then
assuming "gnumeric" is some program that can read from a pipe:

awk -F, -f file.awk file2.csv file2.csv | gnumeric

and to just save the output to a file:

awk -F, -f file.awk file2.csv file2.csv > newfile

> Could you tell me which section of the documentation explains why the
file needs
> to be read twice, please?

It's not a documentation thing, your problem just requires a 2-pass
solution.
The first time to identify which columns always have the null value, the
second
to output just the columns that have at least one non-null value.

> From the command terminal instruction awk, am I right to conclude that
> -F, means "comma is the file delimiter, or separator"?

Yes.

	Ed.