1JOIN(1)                          User Commands                         JOIN(1)
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NAME

6       join - join lines of two files on a common field
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SYNOPSIS

9       join [OPTION]... FILE1 FILE2
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DESCRIPTION

12       For  each  pair of input lines with identical join fields, write a line
13       to standard output.  The default join field is the first, delimited  by
14       blanks.
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16       When FILE1 or FILE2 (not both) is -, read standard input.
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18       -a FILENUM
19              also  print unpairable lines from file FILENUM, where FILENUM is
20              1 or 2, corresponding to FILE1 or FILE2
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22       -e EMPTY
23              replace missing input fields with EMPTY
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25       -i, --ignore-case
26              ignore differences in case when comparing fields
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28       -j FIELD
29              equivalent to '-1 FIELD -2 FIELD'
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31       -o FORMAT
32              obey FORMAT while constructing output line
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34       -t CHAR
35              use CHAR as input and output field separator
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37       -v FILENUM
38              like -a FILENUM, but suppress joined output lines
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40       -1 FIELD
41              join on this FIELD of file 1
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43       -2 FIELD
44              join on this FIELD of file 2
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46       --check-order
47              check that the input is correctly  sorted,  even  if  all  input
48              lines are pairable
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50       --nocheck-order
51              do not check that the input is correctly sorted
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53       --header
54              treat  the  first line in each file as field headers, print them
55              without trying to pair them
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57       -z, --zero-terminated
58              line delimiter is NUL, not newline
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60       --help display this help and exit
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62       --version
63              output version information and exit
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65       Unless -t CHAR is given, leading blanks separate  fields  and  are  ig‐
66       nored,  else fields are separated by CHAR.  Any FIELD is a field number
67       counted from 1.  FORMAT is one or more comma or blank separated  speci‐
68       fications,  each  being 'FILENUM.FIELD' or '0'.  Default FORMAT outputs
69       the join field, the remaining fields from FILE1, the  remaining  fields
70       from  FILE2,  all  separated by CHAR.  If FORMAT is the keyword 'auto',
71       then the first line of each file determines the number of fields output
72       for each line.
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74       Important:  FILE1  and  FILE2 must be sorted on the join fields.  E.g.,
75       use "sort -k 1b,1" if 'join' has no options, or use  "join  -t  ''"  if
76       'sort'  has no options.  Note, comparisons honor the rules specified by
77       'LC_COLLATE'.  If the input is not sorted  and  some  lines  cannot  be
78       joined, a warning message will be given.
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AUTHOR

81       Written by Mike Haertel.
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REPORTING BUGS

84       GNU coreutils online help: <https://www.gnu.org/software/coreutils/>
85       Report any translation bugs to <https://translationproject.org/team/>
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88       Copyright  ©  2021  Free Software Foundation, Inc.  License GPLv3+: GNU
89       GPL version 3 or later <https://gnu.org/licenses/gpl.html>.
90       This is free software: you are free  to  change  and  redistribute  it.
91       There is NO WARRANTY, to the extent permitted by law.
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SEE ALSO

94       comm(1), uniq(1)
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96       Full documentation <https://www.gnu.org/software/coreutils/join>
97       or available locally via: info '(coreutils) join invocation'
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101GNU coreutils 9.0                 March 2022                           JOIN(1)
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