Merge two raw data files.fq.gz into one

[shis]

Hi,
I am a new perl user. I would like to merge two raw data files.fq.gz into one file.fq.gz using perl script. I made this command line:

~/software/Test_perlscripts/mergeGZFastqFiles.pl lane1r2_subset.fq.gz lane1r1_subset.fq.gz 11.r2r1_subset.fq.gz

After writing the above command and hit enter, it says Permission denied


bash: /home/software/Test_perlscripts/mergeGZFastqFiles.pl: Permission denied

Can anyone advice me why this error message came in and how I can fix it?

[dpryan]

chmod a+x ~/software/Test_perlscripts/mergeGZFastqFiles.pl

Also, make sure you have the appropriate shebang at the beginning of the perl file (i.e., something like "#!/usr/bin/env perl").

[GenoMax]

@shis: Unless you are trying to interleave the reads with the perl script, you could also just "cat" them together to make a single file.

[shis]

I have changed according file permission: chmod a+x and execute the command again. Now it says:

Can't open gzip file lane1r2_subset.fq.gz

[GenoMax]

I have changed according file permission: chmod a+x and execute the command again. Now it says:

Can't open gzip file lane1r2_subset.fq.gz

That sounds like a read permission error (as long as the file is in the local directory).

What exactly are you trying to do with the perl script?

Post output for

$ ls -l *.fq.gz

[shis]

@GenoMax: Actually I would like to merge two reads, read1 (Forward) and read2 (reverse) of lane 1 and lane 2 using perl script. For the begining I am trying to test the perl script I have with a subset of lane1 read2 and lane1 read1.

[dpryan]

If you want to merge them based on an overlap (as opposed to just appending one sequence to the other) then you might want to just use Flash.

[bruce01]

How is perl reading in the files? You might use a construct like:

open(IN, "gunzip -c $ARGV[0] |");
while(<IN>){
...
}

It pipes the gunzip call into perl. You can also do same for BAM files eg:

open(IN, "samtools view $bam |");
while(<IN>){
...
}

[GenoMax]

@GenoMax: Actually I would like to merge two reads, read1 (Forward) and read2 (reverse) of lane 1 and lane 2 using perl script. For the begining I am trying to test the perl script I have with a subset of lane1 read2 and lane1 read1.

Perhaps there is something simple that is wrong with your perl script. If you want someone to help you debug the script then you can post it here.

We are assuming that file permissions on the two subset files allow reading by user account that is running the perl script.

It may just be simple to use the program Devon suggested.

[shis]

@GenoMax:

$ ls -l lane1r2_subset.fq.gz

-rw-r--r-- 1 me me 2888777 Apr 14 14:14 lane1r2_subset.fq.gz

[GenoMax]

@GenoMax:

$ ls -l lane1r2_subset.fq.gz

-rw-r--r-- 1 me me 2888777 Apr 14 14:14 lane1r2_subset.fq.gz

Read permission is not the problem. It must be something in your code.

[crazyhottommy]

zcat *fq.gz | gzip > merged.fq.gz

[lindenb]

You don't have to gunzip/gzip. You can just concatenate gz files ( http://stackoverflow.com/questions/8005114 )

cat f1.gz f2.gz > merged.gz

[GenoMax]

zcat *fq.gz | gzip > merged.fq.gz

@shis (post # 6) does not want to merge the files but the R1/R2 reads (overlap them).