gene's ID extraction

Question

[paraskevopou]

Dear people, I have 2 txt files, file1.txt with long ID's names (e.g TRINITY_DN14306_c0_g3_i4) and file2.txt with the ID's of my interest, however the isoform information is missing (e.g. TRINITY_DN14306_c0_g3). File1 has 40000 records while file2 has 5000. I would like to extract these 5000 from file1 along with the isoform information. I used the following command but the output I get is empty.

while read line; do grep -e "${line}_" file1.txt; done < file2.txt > out.txt

Any suggestions will be helpful. Thanks a lot in advance! Sofia

[Pierre Lindenbaum]

please, validate or comment your previous questions:

• Comparing vcf files
• vcf files - extract SNPs

If an answer was helpful you should upvote it, if the answer resolved your question you should mark it as accepted.

[Pierre Lindenbaum]

however the isoform information is missing (e.g. TRINITY_DN14306_c0_g3)

please, provide a sample of each files.

[paraskevopou]

Thanks a lot for the comments. Here are mi files. I want to extract only the names that are present on file2.txt from file1.txt. But in file1.txt there is the isoform information (_i*) which I also need in my output file.

file1.txt

TRINITY_DN12874_c0_g1_i1
TRINITY_DN12795_c0_g1_i2
TRINITY_DN12248_c0_g1_i1
TRINITY_DN12868_c0_g1_i1
TRINITY_DN12866_c0_g1_i1
TRINITY_DN12817_c1_g1_i1
TRINITY_DN12775_c1_g2_i2
TRINITY_DN12829_c0_g1_i1
TRINITY_DN12736_c0_g1_i1
TRINITY_DN12865_c0_g1_i1

file2.txt

TRINITY_DN12874_c0_g1
TRINITY_DN12248_c0_g1
TRINITY_DN12866_c0_g1
TRINITY_DN12817_c1_g1

[grant.hovhannisyan]

-e is for multiple pattern matching, while you have one per iteration. But I am not sure if this could matter.

[Ram]

It is helpful if you have extended regular expressions, such as capture groups or even character classes in certain instances. I've rarely ever gone wrong with using an -e when it's not really needed. I've found that more often than not, expected behavior is seen with -e (or -P) than without. Plus, it's easier to build on.