how to find null column

Shell Programming and Scripting
1

Hi, everyone
I have a requirement as following:
source file
1, abc, def, caaa
2, , cde, aaa
3, bcd, , adefefg
I need find columns which contains null value, in above example,
I need get two rows
2, , cde, aaa
3, bcd, , adefefg
anybody has idea how to achive this

thanks in advance

2 
 awk -F, ' {for(i=1;i<=NF;++i) { s=$i; gsub(/ +/, "", s); if(s=="") { print; break; }} } ' infile OFS=,
3 
grep ", ," infile
4

Hi ken002,

I am sure that experts will help you with a nice command, however with my very basic knowledge I would do this:

grep ", ," input file > output file
5

Good idea, but this will be better.

grep ", *," infile
6

Thanks everybody for your quick response