How to delete columns?

how does your cut command look like?

$ cut -d" " -f1,6- filefe120b99164f151b28bf86afa6389b22 186 2010-03-14 19:26 Descript.txt41705ea936cfc653f273b5454c1cdde6  30 2010-03-14 20:29 listof.txt0e25cca3222d32fff43563465af03340  28 2010-03-14 23:35 sedexample.txtd41d8cd98f00b204e9800998ecf8427e   0 2010-02-16 15:11 test1.txtd41d8cd98f00b204e9800998ecf8427e   0 2010-02-16 15:11 test2.txtd41d8cd98f00b204e9800998ecf8427e   0 2010-02-16 15:11 test3.txtd41d8cd98f00b204e9800998ecf8427e   0 2010-02-16 15:11 test4.txtd41d8cd98f00b204e9800998ecf8427e   0 2010-02-16 15:11 test5.txtd41d8cd98f00b204e9800998ecf8427e   0 2010-02-16 15:11 test6.txtf5c7f1856249d0526be10df5bd5b895a  26 2010-03-13 14:13 testingfile.txtd41d8cd98f00b204e9800998ecf8427e   0 2010-03-15 00:28 uniquelist.txt

redirect to new file as needed.

Or awk

$ awk '{$2=$3=$4=$5="";gsub(/ +/," ")}1' filefe120b99164f151b28bf86afa6389b22 186 2010-03-14 19:26 Descript.txt41705ea936cfc653f273b5454c1cdde6 30 2010-03-14 20:29 listof.txt0e25cca3222d32fff43563465af03340 28 2010-03-14 23:35 sedexample.txtd41d8cd98f00b204e9800998ecf8427e 0 2010-02-16 15:11 test1.txtd41d8cd98f00b204e9800998ecf8427e 0 2010-02-16 15:11 test2.txtd41d8cd98f00b204e9800998ecf8427e 0 2010-02-16 15:11 test3.txtd41d8cd98f00b204e9800998ecf8427e 0 2010-02-16 15:11 test4.txtd41d8cd98f00b204e9800998ecf8427e 0 2010-02-16 15:11 test5.txtd41d8cd98f00b204e9800998ecf8427e 0 2010-02-16 15:11 test6.txtf5c7f1856249d0526be10df5bd5b895a 26 2010-03-13 14:13 testingfile.txtd41d8cd98f00b204e9800998ecf8427e 0 2010-03-15 00:28 uniquelist.txt

Easily done as a shell pipe.

cut --delimiter=' ' --fields=3-5 --complement

If you really need to do this in C, you could run that command in a subprocess via popen.

If you had mixed space and tab delimiters, you would need to convert one to the other as cut does not like multiple delimiters. Do this with tr or col -x.

Pipe it through awk '{print $1 $6 $7 $8 $9;}'?