Grep for searching pattern in a file

Question

I want to use grep to search pattern from one file in a second one. My pattern file is something like:

K02217
K07448
KO8980

The file to search in is:

>aai:AARI_24510  proP; proline/betaine transporter; K03762 MFS transporter, MHS family, proline/betaine transporter
>aai:AARI_26600  ferritin-like protein; K02217 ferritin [EC:1.16.3.1]
>aai:AARI_28260  hypothetical protein
>aai:AARI_29060  ABC drug resistance transporter, inner membrane subunit; K09686 antibiotic transport system permease protein
>aai:AARI_29070  ABC drug resistance transporter, ATP-binding subunit (EC:3.6.3.-); K09687 antibiotic transport system ATP-binding protein
>aai:AARI_29650  hypothetical protein
>aai:AARI_32480  iron-siderophore ABC transporter ATP-binding subunit (EC:3.6.3.-); K02013 iron complex transport system ATP-binding protein [EC:3.6.3.34]
>aai:AARI_33320  mrr; restriction system protein Mrr; K07448 restriction system protein

The command I tried is:

fgrep --file=pattern.txt file.txt >> output.txt

This prints the lines of file.txt where the pattern is found. I need it to print also a column with the pattern found. So something like:

K07448 mrr; restriction system protein Mrr; K07448 restriction system
K02217 ferritin-like protein; K02217 ferritin [EC:1.16.3.1]

Anyone can suggest me how to do?

Answer 1

If you don't mind an extra column with a number in it you can use join and grep to do this.

$ join <(grep -of patterns.txt file.txt | nl) \
       <(grep -f patterns.txt file.txt | nl)
1 KO3322 proteinaseK (KO3322)
2 KO3435 Xxxxx KO3435;folding factor
3 KO3435 Yyyyy KO3435,xxxx

Answer 2

You can use a shell loop:

$ while read pat; do 
    grep "$pat" file | 
        while read match do 
            echo -e "$pat\t$match"
        done
 done < patterns 
KO3435  Xxxxx KO3435;folding factor
KO3435  Yyyyy KO3435,xxxx
KO3322  proteinaseK (KO3322)

I tested by running this on the UniProt flat file for human (625M) and using 1000 UniProt IDs as the patterns. It took ~6 minutes on my Pentium i7 laptop. It took ~35 seconds when I only looked for 100 patterns.

---

As pointed out in the comments below, you can make this slightly faster by skipping the echo and using grep's --label and -H options:

$ while read pat; do 
    grep "$pat" --label="$pat" -H < file
done < patterns

---

Running this on your example files produces:

$ while read pat; do 
    grep "$pat" --label="$pat" -H < kegg.annotations; 
  done < allKO.IDs.txt > test1
terdon@oregano foo $ cat test1 
K02217:>aai:AARI_26600  ferritin-like protein; K02217 ferritin [EC:1.16.3.1]
K07448:>aai:AARI_33320  mrr; restriction system protein Mrr; K07448 restriction system protein

Answer 3

You can use ack:

$ ack "$(tr '\n' '|' < pattern.txt | sed -e 's/.$//')" --print0 --output='$& $_' file.txt
KO3322 proteinaseK (KO3322)
KO3435 Xxxxx KO3435;folding factor
KO3435 Yyyyy KO3435,xxxx