hey all, I have this file looks like this A = [ 1 2 3 4 5 6 7 8 9 10 11 12 12 12 12 13 14 15 16 17 18 19 20 21 ] i wanted to get rid of 2nd row and 5th row. any row that doesnt have the same column as the previous one. my problem in matlab is it will take too long. since i have about 13000 rows and 46 coulmns. can someone help w/ unix script. thanks, Gpatel thanks, Gaurav

So, I'm assuming that you need to NOT process 'A = [' in the first line and ' ]' in the last line? If that's the case, these characters need to be retained?

yes the file just look like this 1 2 3 4 5 6 7 8 9 10 11 12 12 12 12 13 14 15 16 17 18 19 20 21 there is no A and []; file only has numbers and some rows are different then others. i wanted to delete those rows which are different. thanks for your help nails. ~gpatel thanks, Gaurav

I meant to say differnt columns now rows. thanks, Gaurav

Here's my take: Read each line, determining the number of fields in each line. If the next line has the same number of lines, print it else if it doesn't delete it. When a line is deleted start the field count over: awk ' BEGIN { cnt=0 } { if (cnt == 0) { pf=NF cnt++ print $0 continue } if(cnt == 1) { if(pf == NF) print $0 else cnt=0 } } ' data.file # end script In case you don't know, awk sets NF to the number of fields for the line read. Let me know if you have any questions.

Thanks a lot. i know little bit about awk but thanks for explanation. I am going to try this and i will let you know. thanks one again.