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randomly select lines from a list

Comment:

Hi all, I have a text file that has 142 lines each containing several columns. I'm trying to write a script that will randomly choose half of the lines, then write these to a new text file. So, the result would be a file similar to the original, but containing only 71 lines with none repeating. Any advice/help would be greatly appreciated. Nickles b

Name: nails
Date: April 15, 2008 at 13:17:42 Pacific

Reply:

Take a look at this thread: http://www.computing.net/answers/un... It describes using the shell's RANDOM number generator. It doesn't talk about repeating lines. You'll have to save the lines already used.

0

Name: ghostdog
Date: April 16, 2008 at 03:33:01 Pacific

Reply:

awk 'BEGIN{srand()} !/^$/{ a[c++]=$0} END { for ( i=1;i<=c ;i++ ) { num=int(rand() * c) if ( a[num] ) { print a[num] delete a[num] d++ } if ( d == c/2 ) break } }' file

0

copy and past in a file

AWK or some search

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