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Full Discussion: Sed on first instance only
Top Forums Shell Programming and Scripting Sed on first instance only Post 302288540 by vgersh99 on Tuesday 17th of February 2009 01:51:04 PM
Old 02-17-2009
Quote:
Originally Posted by otheus
sed might not be the best tool here. However, GNU sed might work for you. Put all your substitutions, one line each, in "file2". And run sed on file1. Note, the newline in the middle of the sed script is necessary:
Code:
sed '/^0${ R file2
;d;}' file1

I have a gut feeling that the OP cannot predict what rows will be 'missing'. So gut is telling me the OP wants to derive the value of the missing row from the previous row value. In which case we'll have to know if the sample file is representative of the 'real life' data and what (if any) assumptions can be made regarding the data itself.

Once again, this is all guesses on my part....
 

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diff3(1)						      General Commands Manual							  diff3(1)

Name
       diff3 - 3-way differential file comparison

Syntax
       diff3 [-ex3] file1 file2 file3

Description
       The command compares three versions of a file, and publishes the ranges of text that disagree, flagged with the following codes:

	  ====	      all three files differ

	  ====1       file1 is different

	  ====2       file2 is different

	  ====3       file3 is different

       The type of change needed to convert a given range of a given file to some other is indicated in one of these ways:

	  f : n1 a    Text is to be appended after line number n1 in file f, where f = 1, 2, or 3.

	  f : n1 , n2 c
		      Text is to be changed in the range line n1 to line n2.  If n1 = n2, the range may be abbreviated to n1.

       The original contents of the range follows immediately after a c indication.  When the contents of two files are identical, the contents of
       the lower-numbered file is suppressed.

Options
       -3   Produces an editor script containing the changes between file1 and file2 that are to be incorporated into file3.

       -e	   Produces an editor script containing the changes between file2 and file3 that are to be incorporated into file1.

       -x	   Produces an editor script containing the changes among all three files.

Examples
       Under the -e option, publishes a script for the editor that incorporates into file1 all changes between file2 and  file3  -  that  is,  the
       changes	that would normally be flagged ==== and ====3.	Option -x (-3) produces a script to incorporate only changes flagged ==== (====3).
       The following command applies the resulting script to `file1':
       (cat script; echo '1,$p') | ed - file1

Restrictions
       Text lines that consist of a single `.'	defeat -e.

Files
       /tmp/d3?????
       /usr/lib/diff3

See Also
       cmp(1), comm(1), diff(1), dffmk(1), join(1), sccsdiff(1), uniq(1)

																	  diff3(1)
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