1samtools-merge(1)            Bioinformatics tools            samtools-merge(1)
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NAME

6       samtools merge - merges multiple sorted files into a single file
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SYNOPSIS

9       samtools merge [options] -o out.bam [options] in1.bam ... inN.bam
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11       samtools merge [options] out.bam in1.bam ... inN.bam
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DESCRIPTION

15       Merge multiple sorted alignment files, producing a single sorted output
16       file that contains all the input records  and  maintains  the  existing
17       sort order.
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19       The output file can be specified via -o as shown in the first synopsis.
20       Otherwise the first non-option filename argument is taken to be out.bam
21       rather  than an input file, as in the second synopsis.  There is no de‐
22       fault; to write to standard output (or to a pipe), use either “-o -” or
23       the equivalent using “-” as the first filename argument.
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25       If  -h  is specified the @SQ headers of input files will be merged into
26       the specified header, otherwise they will be merged  into  a  composite
27       header  created  from  the input headers.  If in the process of merging
28       @SQ lines for coordinate sorted input files, a conflict  arises  as  to
29       the  order (for example input1.bam has @SQ for a,b,c and input2.bam has
30       b,a,c) then the resulting output file will need to  be  re-sorted  back
31       into coordinate order.
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33       Unless  the  -c or -p flags are specified then when merging @RG and @PG
34       records into the output header then any IDs found to be  duplicates  of
35       existing  IDs  in the output header will have a suffix appended to them
36       to differentiate them from similar header records from other files  and
37       the read records will be updated to reflect this.
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39       The  ordering of the records in the input files must match the usage of
40       the -n and -t command-line options.  If they do not, the  output  order
41       will be undefined.  See sort for information about record ordering.
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44       -1      Use Deflate compression level 1 to compress the output.
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46       -b FILE List of input BAM files, one file per line.
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48       -f      Force to overwrite the output file if present.
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50       -h FILE Use  the  lines of FILE as `@' headers to be copied to out.bam,
51               replacing any header lines that would otherwise be copied  from
52               in1.bam.  (FILE is actually in SAM format, though any alignment
53               records it may contain are ignored.)
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55       -n      The input alignments are sorted by read names  rather  than  by
56               chromosomal coordinates
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58       -o FILE Write merged output to FILE, specifying the filename via an op‐
59               tion rather than as the first filename argument.   When  -o  is
60               used,  all non-option filename arguments specify input files to
61               be merged.
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63       -t TAG  The input alignments have been sorted by the value of TAG, then
64               by either position or name (if -n is given).
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66       -R STR  Merge files in the specified region indicated by STR [null]
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68       -r      Attach  an  RG tag to each alignment. The tag value is inferred
69               from file names.
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71       -u      Uncompressed BAM output
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73       -c      When several input files contain @RG headers with the same  ID,
74               emit  only  one of them (namely, the header line from the first
75               file we find that ID in) to the merged output file.   Combining
76               these similar headers is usually the right thing to do when the
77               files being merged originated from the same file.
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79               Without -c, all @RG headers appear in  the  output  file,  with
80               random suffixes added to their IDs where necessary to differen‐
81               tiate them.
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83       -p      Similarly, for each @PG ID in the set of files  to  merge,  use
84               the  @PG  line of the first file we find that ID in rather than
85               adding a suffix to differentiate similar IDs.
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87       -X      If this option is set, it will allows user to  specify  custom‐
88               ized index file location(s) if the data folder does not contain
89               any index file. See EXAMPLES section for sample of usage.
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91       -L FILE BED file for specifying multiple regions  on  which  the  merge
92               will  be performed.  This option extends the usage of -R option
93               and cannot be used concurrently with it.
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95       --no-PG Do not add a @PG line to the header of the output file.
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97       -@, --threads INT
98               Number of input/output compression threads to use  in  addition
99               to main thread [0].
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EXAMPLES

103       o Attach the RG tag while merging sorted alignments:
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105           perl -e 'print "@RG\tID:ga\tSM:hs\tLB:ga\tPL:Illumina\n@RG\tID:454\tSM:hs\tLB:454\tPL:454\n"' > rg.txt
106           samtools merge -rh rg.txt merged.bam ga.bam 454.bam
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108         The value in a RG tag is determined by the file name the read is com‐
109         ing from. In this example, in the merged.bam, reads from ga.bam  will
110         be  attached  RG:Z:ga,  while  reads  from  454.bam  will be attached
111         RG:Z:454.
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114       o Include customized index file as a part of arguments:
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116           samtools merge [options] -X <out.bam> </data_folder/in1.bam> [</data_folder/in2.bam> ... </data_folder/inN.bam>] </index_folder/index1.bai> [</index_folder/index2.bai> ... </index_folder/indexN.bai>]
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AUTHOR

121       Written by Heng Li from the Sanger Institute.
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SEE ALSO

125       samtools(1), samtools-sort(1), sam(5)
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127       Samtools website: <http://www.htslib.org/>
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131samtools-1.15.1                  7 April 2022                samtools-merge(1)
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