I have a text file. the first line constans of the titles. and i have an one large file which has over 70,000 lines. and some of the line, has a test cases. to test programs in a big file, it took over 10minutes. $cat file.csv "title"||"title2"||"title3" "data"||"data2"||"data3" ...... $wc -l file.csv 77488 file.csv #split it by lines $split -l 10,000 file.csv myfile $ls myfile* myfileaa myfileab myfileac myfilead myfileae myfileaf myfileag myfileah $cat myfileaa > myfile_01 $head -1 myfileaa | cat - myfileab > myfile_02 $head -1 myfileaa | cat - myfileac > myfile_03 $head -1 myfileaa | cat - myfilead > myfile_04 $head -1 myfileaa | cat - myfileae > myfile_05 $head -1 myfileaa | cat - myfileaf > myfile_06 $head -1 myfileaa | cat - myfileag > myfile_07