I have two files.One file contains blast result of contigs and the next file contains the contigs that are used for blast.I want an output text file of sequences in a separate folder which gives no hits in blast result from original fasta file with all contigs. I have no idea about this.Can you please help me to create perl script for this problem.
<p><strong>1)</strong> Extract names of contigs without hit in blast:</p>

<pre>
grep -B5 &quot;***** No hits found&quot; blast.txt | grep Query | sed &#39;s/Query= //g&#39; &gt; ids</pre>

<p><strong>2) </strong>Extract fasta records of those contigs without hit:</p>

<pre>
cat ids | xargs -n 1 samtools faidx contigs.fa &gt; contigs_nohit.fa</pre>
