Using sed to do string substitution

[pdtt]

Hi,

I am new to sed. I have to modify a tab delimitted text file that is not formatted correctly for my use. I have to do a replacement.
I have date fields that are formatted like this:
mm/dd/yyyy. If the date field is null, the file is outputting / / .

If I know what number tab the field starts with, can I wrap the good dates with double quotes so they end up like this: "mm/dd/yyyy" and can I strip out the / / fields and replace them with ""?

Any help is much appreciated.

Thank you

 

[CaKiwi]

I don't understand what you want. Post some sample input and output data.

CaKiwi

"I love mankind, it's people I can't stand" - Linus Van Pelt

 

[SamBones]

Well, if I'm reading your question right, try this. Let's say your date is between the third and fourth tab, and if it's not a valid date, it is "

<space>/<space>/<space>

". You could do something like this. Say our sample tab delimited file is called file.dat and looks like this...

   one     ab      fish    04/07/60        yellow
   five    jT      shoe    05/03/03        blue
   two     Ks      knee     / /    yellow
   nine    wM      corn    07/04/76        orange

...running the following command...

   sed 's/<tab>/<tab>&quot;/3;s/<tab>/&quot;<tab>/4;s= / / ==g' file.dat

...where you actually hit the tab key where I put

<tab>

. So it would look more like...

   sed 's/ /       "/3;s/  /"      /4;s= / / ==g' file.dat

This should convert the file to...

   one     a       fish    "04/07/60"      yellow
   five    j       shoe    "05/03/03"      blue
   two     K       knee    ""      yellow
   nine    w       corn    "07/04/76"      orange

...which I think is what you want.

Hope this helps.

 

[pdtt]

Yes, SamBones, this is what I want. Thank you very much