S:\>perl.exe -nle"1+index($_, 'clanks') and print" 8gb.txt | wc -l
   2048

##</code><code>##

S:\>grep -F clanks 8gb.txt | wc -l
   2048

##</code><code>##

S:\>perl -le"while(<>){ 1+index($_, 'clanks') and print; }" 8gb.txt | wc -l
   4096