[ale] Another Large File/PERL/Awk/Sed question...

[Richard at Bronosky.com (Richard Bronosky)]

in sed, use '[range/line number]{commands}' to limit where the edits
are made. Example:
mount |sed '1{s/type/TEST/}'

what you want is:
sed -i.bak '1{s/column4/column5/}' filename

A backup filename.bak will be created with that command. drop the
-i.bak if you don't want it.


On Tue, Dec 1, 2009 at 4:06 PM, Bob Kruger <bkruger at mindspring.com> wrote:
> All;
>
> Thanks to all who assisted me with my earlier question on deleting the semicolon from the end of a line. ?I have another one that may be a bit stickier.
>
> Again I have a large data file in text format, this one is 3.2GB. ?Same as before, the field are semicolon delimited. ?The first line of the file is the column name. ?However, I have two columns that were inadvertently given the same column name.
>
> Example:
>
> column1;column2;column3;column4;column4;column6;column7....
>
> I would like to change the second instance of column4 to column5 on the first line of the file. ?I thought it would be simple to fire up vi and just do a simple text edit. ?The edit part was simple, but the saving of the file is taking hours.
>
> Any thoughts or ideas using PERL, Awk, or Sed?
>
> Thanks in advance for any assistance.
>
> V/r
>
> Bob
>
>
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.!# RichardBronosky #!.