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Parse a CSV file extracting some of the values but not all.

Answer 1

A:

Here's a shell script solution.

egrep 'category4|category2' input.file | cut -d"," -f1,3 | sort -u > output.file

I used the cut command just to show you that you can extract certain columns only, since the f switch for cut chooses, which columns you want to extract.

The u switch for sort makes the output to be unique.

Edit: It's important that you use egrep and not grep, since grep uses a somewhat restricted regular expression set, and egrep has somewhat further facilities

Edit (for people who only have grep available):

grep 'category2' input.file > temp.file && grep 'category4' input.file >> temp.file && cut temp.file -d"," -f1,3 | sort -u > output.file && rm temp.file

It produces quite an overhead but still works...

dare2be 2010-05-19 04:18:08

Thank you dare2be much appreciated.The `cut` portion works great alone (new to me),but when I use the full command with egrep to do the restriction it produces an empty file.

Yallaa 2010-05-19 04:44:49

now that's weird. See, to check whether I copied it properly from terminal to SO, I copy-and-pasted it to terminal and it worked... Are you sure you have `egrep` installed? Check with `which egrep`

dare2be 2010-05-19 04:50:08

It is installed`> which egrep /bin/egrep > ls -l /bin/egrep lrwxrwxrwx 1 root root 4 Mar 1 2008 /bin/egrep -> grep `I tried both grep and egrep and same thing no output.

Yallaa 2010-05-19 05:01:23

Haha you see, `egrep` is linked to `grep`, so you actually DON'T have `egrep` and the regular expression I posted won't work in `grep`. Try the non-egrep version I just posted.

dare2be 2010-05-19 05:04:55

Is egrep linked to grep or the other way around above?I actually have both actual files /bin/egrep /bin/grep.I tried your new example and it works, thanks a million.But then I went back and did the first one with egrep but used the full path with egrep like so /bin/egrep and it worked perfectly this time. So it is an issue with the env. path.

Yallaa 2010-05-19 05:12:06

Both solutions work perfectly... Thank you!!

Yallaa 2010-05-19 05:13:51

You're welcome. Choose my answer to tag the question as solved, if you may..

dare2be 2010-05-19 05:21:37

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Parse a CSV file extracting some of the values but not all.

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