how to merge fastq files

[sazz]

Hello all,

I got my fastq files after sequencing, but they sent them in 5 pieces for 1 sample. Do you know a way to merge them?

Thanks!

[mastal]

Use 'cat' from the command line;

In the directory containing your fastq files:

$ cat *.fastq > merged.fastq

[sazz]

I keep getting "-bash: *.fastq: Permission denied" even though I have read - write and execute permissions (-rwxrwxrwx) :/ But thanks for the command, I will try to make it work.

[GenoMax]

Are your files are in the *.fastq.gz format? Is so, you need to amend mastal's command as follows:

$ cat *.fastq.gz > merged_file.fastq.gz

It is probably not required but you could keep the sequence of the pieces intact like this:

cat Sample_ATCACG_L002_R1_001.fastq.gz Sample_ATCACG_L002_R1_002.fastq.gz > Sample_ATCACG_L002_R1_combined.fastq.gz

[mastal]

Maybe your system has a problem with using the wildcard * ?

Since you just have 5 files, try listing the individual file names,

$ cat file1.fastq file2.fastq file3.fastq file4.fastq file5.fastq > merged.fastq

[sazz]

I have unpacked them before and they are all in .fastq format. I tried like you wrote, in the long form as:

sudo cat I-1_ATCACG_L002_R1_001.fastq I-1_ATCACG_L002_R1_002.fastq I-1_ATCACG_L002_R1_003.fastq I-1_ATCACG_L002_R1_004.fastq I-1_ATCACG_L002_R1_005.fastq > I-1.fastq

Still give the same error:

-bash: I-1.fastq: Permission denied

But what I have realized is that; I have other fastq files (from a previous sequencing but in 1 piece for each sample), they are colored in "white" in the bash screen and before, I used split option on those and it worked fine; but this time, those new fastq files are colored green. This means anything?

[GenoMax]

Hmm. You should not have to "sudo" to "cat" files. It looks to me like you do not have write permissions on the directory where these files are residing.

See if this works. This will put the merged file in your $HOME where you should have write permissions.

cat I-1_ATCACG_L002_R1_001.fastq I-1_ATCACG_L002_R1_002.fastq I-1_ATCACG_L002_R1_003.fastq I-1_ATCACG_L002_R1_004.fastq I-1_ATCACG_L002_R1_005.fastq > ~/I-1.fastq

[sazz]

Worked like a dream ! thanks GenoMax.