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PORECHOP(1) User Commands PORECHOP(1)

NAME

porechop - adapter trimmer for Oxford Nanopore reads

SYNOPSIS

porechop [-h] -i INPUT [-o OUTPUT] [--format {auto,fasta,fastq,fasta.gz,fastq.gz}] [-v VERBOSITY] [-t THREADS] [--version] [-b BARCODE_DIR] [--barcode_threshold BARCODE_THRESHOLD] [--barcode_diff BARCODE_DIFF] [--require_two_barcodes] [--untrimmed] [--discard_unassigned] [--adapter_threshold ADAPTER_THRESHOLD] [--check_reads CHECK_READS] [--scoring_scheme SCORING_SCHEME] [--end_size END_SIZE] [--min_trim_size MIN_TRIM_SIZE] [--extra_end_trim EXTRA_END_TRIM] [--end_threshold END_THRESHOLD] [--no_split] [--discard_middle] [--middle_threshold MIDDLE_THRESHOLD] [--extra_middle_trim_good_side EXTRA_MIDDLE_TRIM_GOOD_SIDE] [--extra_middle_trim_bad_side EXTRA_MIDDLE_TRIM_BAD_SIDE] [--min_split_read_size MIN_SPLIT_READ_SIZE]

DESCRIPTION

Porechop: a tool for finding adapters in Oxford Nanopore reads, trimming them from the ends and splitting reads with internal adapters

OPTIONS

optional arguments:

show this help message and exit

Main options:

FASTA/FASTQ of input reads or a directory which will be recursively searched for FASTQ files (required)
Filename for FASTA or FASTQ of trimmed reads (if not set, trimmed reads will be printed to stdout)
Output format for the reads - if auto, the format will be chosen based on the output filename or the input read format (default: auto)
Level of progress information: 0 = none, 1 = some, 2 = lots, 3 = full - output will go to stdout if reads are saved to a file and stderr if reads are printed to stdout (default: 1)
Number of threads to use for adapter alignment (default: 4)
show program's version number and exit

Barcode binning settings:

Control the binning of reads based on barcodes (i.e. barcode demultiplexing)
Reads will be binned based on their barcode and saved to separate files in this directory (incompatible with --output)
A read must have at least this percent identity to a barcode to be binned (default: 75.0)
If the difference between a read's best barcode identity and its second-best barcode identity is less than this value, it will not be put in a barcode bin (to exclude cases which are too close to call) (default: 5.0)
Reads will only be put in barcode bins if they have a strong match for the barcode on both their start and end (default: a read can be binned with a match at its start or end)
Bin reads but do not trim them (appropriate if reads are to be used with Nanopolish) (default: trim the reads)
Discard unassigned reads (instead of creating a "none" bin) (default: False)

Adapter search settings:

Control how the program determines which adapter sets are present
An adapter set has to have at least this percent identity to be labelled as present and trimmed off (0 to 100) (default: 90.0)
This many reads will be aligned to all possible adapters to determine which adapter sets are present (default: 10000)
Comma-delimited string of alignment scores: match, mismatch, gap open, gap extend (default: 3,-6,-5,-2)

End adapter settings:

Control the trimming of adapters from read ends
The number of base pairs at each end of the read which will be searched for adapter sequences (default: 150)
Adapter alignments smaller than this will be ignored (default: 4)
This many additional bases will be removed next to adapters found at the ends of reads (default: 2)
Adapters at the ends of reads must have at least this percent identity to be removed (0 to 100) (default: 75.0)

Middle adapter settings:

Control the splitting of read from middle adapters
Skip splitting reads based on middle adapters (default: split reads when an adapter is found in the middle)
Reads with middle adapters will be discarded (default: reads with middle adapters are split) (this option is on by default when outputting reads into barcode bins)
Adapters in the middle of reads must have at least this percent identity to be found (0 to 100) (default: 85.0)
This many additional bases will be removed next to middle adapters on their "good" side (default: 10)
This many additional bases will be removed next to middle adapters on their "bad" side (default: 100)
Post-split read pieces smaller than this many base pairs will not be outputted (default: 1000)

AUTHOR

This manpage was written by Andreas Tille for the Debian distribution and can be used for any other usage of the program.

August 2018 porechop 0.2.3