# Choose first N FASTA records
perl -ne 'BEGIN {$/=">";$o=0}{chomp;$o<N?(/^$/?next:print">$_"):last;$o++}' EXAMPLE.fa

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 perl -ne 'BEGIN{$/=">";$o=0}{chomp;$o<22?(/^$/?next:print">$_"):last;$o++}' b4x_est100.fa # print the first 22 records