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

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.

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