perl -le 'BEGIN{$,=","} print map int rand 1000, 1..2500 for 1..547_183' > infile.csv

[sk]% time wc -l infile.csv
 547183 numbers.csv
2.730u 11.660s 1:32.06 15.6%    

[sk]% time perl -nle '$line++; print +($line-1) if eof;' infile.csv
547183
19.600u 4.560s 0:24.16 100.0%   

##</code><code>##

% head -10000 inputfile > smallfile

% script smallfile