for filename in *.fa; do sed -i '/>Recurrent fasta name/c\>'$filename'' $filename; done ==== all VCF to vcf.gz ==== ls *.vcf | xargs -n1 -P0 bgzip ===== AWK ===== awk '{if(NR%4==2) {count++; bases += length} } END{print bases/count}' # keep online lines with col 5 & 4 of length == 1char zgrep -v "\.\/\.:\." Merged.vcf.gz | awk '{if (length($5)==1 && length($4)==1) print $line}' Find last modified files from active directory. find $1 -type f -exec stat --format '%Y :%y %n' "{}" \; | sort -nr | cut -d: -f2- | head