BOL

Extract the underscore separated values. $ awk '{split($0,a,"_"); print a[1]"_"a[2]}' aaa.txt | sort | uniq -u > all_ids_sm.txt #awk #bash #underscore #list

Multiline to singleline covert. $ awk '/^>/ {printf("%s%s\t",(N>0?"\n":""),$0);N++;next;} {printf("%s",$0);} END {printf("\n");}' < input.fa #Multi #Single #Convert #awk

Remove duplicated lines from text file. $ awk '!seen[$0]++' allIds #duplicate #lines #remove #awk

Replace space with tab. $ awk -v OFS="\t" '$1=$1' file1 #tab #space #replace #awk

Rename/number the multi-fasta file in ascending order. $ awk '/^>/{print ">" ++i; next}{print}' < Mix_assembly.fasta > Mix_assembly2.fasta #awk #oneliner

Print all the values beetween a pattern "abc" > awk '/abc/{flag=1;next}/mno/{flag=0}flag' file #awk #print #range #pattern