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Formatting a file - Remove Duplicate


 
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# 1  
Old 06-07-2011
Question Formatting a file - Remove Duplicate

Hi I have a file in the following format. Basically the file contains tablename and their aliases:

TABLE1
TABLE1 A
TABLE2
TABLE2 B
TABLE3
TABLE4
TABLE4 C
TABLE4

Upon formatting an sql statement I am getting such output.

Problem: Whenever a tablename appears with alias, it has repeated entries in the file. One without alias, and one with alias. I want to remove the first occurance of the tablename (without aliases). but there might be some entries with tablename without any alias, don't wanna delete those. also there can be a repetition of same table, and one could be with alias one could be without alias.

Solution: Basically just want to delete the line which preceeds with tablename with alias. so the output should be like:

TABLE1 A
TABLE2 B
TABLE3
TABLE4 C
TABLE4

Hope I am clear enough.
Your help would be much appreciated. Thanks.
# 2  
Old 06-07-2011
Java

Try sort -u

Code:
shell>less file
TABLE1
TABLE1 A
TABLE2
TABLE2 B
TABLE3
TABLE4
TABLE4 C
TABLE4

shell> sort -u file

TABLE1
TABLE1 A
TABLE2
TABLE2 B
TABLE3
TABLE4
TABLE4 C

I noticed that in your output you dropped TABLE1 but kept TABLE4. Was that intentional?
# 3  
Old 06-07-2011
try this.. not tested..

Code:
awk '{ first_line = $0; getline next_line; if (index($next_line,$first_line) > 0) print $next_line; else print $0; }' filename

# 4  
Old 06-07-2011
Quote:
Originally Posted by ni2
Try sort -u

I noticed that in your output you dropped TABLE1 but kept TABLE4. Was that intentional?
Yeah... Second call for TABLE4 is not having any alias, so that entry shouldn't be deleted
# 5  
Old 06-07-2011
try sed..
Code:
  sed 'N;/\(.*\)\n\(\1 .\)/{s//\2/}' inputfile | sort -u

This User Gave Thanks to michaelrozar17 For This Post:
# 6  
Old 06-07-2011
Quote:
Originally Posted by freakygs
Yeah... Second call for TABLE4 is not having any alias, so that entry shouldn't be deleted
Try the sed example michaelrozar17 posted. Looks like it meets your requirement.

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