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join                         Command                         join




Join two data bases

jjooiinn [-aa [_n] ] [-ee _s_t_r_i_n_g ] [-jj[_n] _k_e_y_f] [-oo _n._m ...] [-tt_c] _f_i_l_e_1 _f_i_l_e_2

join processes the text files file1 and file2, each of which con-
tains a  relational data base.   If either file name  is `-', the
standard input is used for that file.

For the  purposes of  join, a  data base file  contains a  set of
records, one  per input line.   Each record contains  a number of
fields.  One field is  differentiated as key field for each file.
Each file must be sorted by key field, for example with sort.

By default, the key field is the first field in each record.  The
-j option  changes the key  field number to keyf  for the desired
file.  In this and  other options below, the optional file number
n must be 1 to indicate file1 or 2 to indicate file2.  If no n is
given, both file1 and file2 are assumed.

Normally,  fields are  separated  by any  amount  of white  space
(blanks or tabs).  Leading blanks or tabs are not considered part
of the fields.  With the -t option, the separator character is c.
With this  option zero-length  fields are possible;  every occur-
rence of  the separator ends the previous field  and starts a new
one.

Output consists only of records for which the key field occurs in
both files.   As a consequence of the sorted  order of the input,
the output  is also sorted by the key  field.  Each output record
has first  the key field,  then each field from  the file1 record
but the key field, and then  each field from the file2 record but
the  key field.   Fields  are separated  in the  output with  the
specified field  character, or  with a  space character if  no -t
option was  given.  Output records  are always terminated  with a
newline.  Under  the -e option, string is  printed for each empty
field.

The -a  option enables printing of records found  in only file n.
If n  is missing,  unpaired records  are printed from  both input
files.  To  output only certain fields, the  -o option precedes a
list of desired fields to print.  Each element is of the form n.m
where n is the file number and m is the field number.

For example,


        join -t: -j1 3 -o 1.3 2.4 1.4 1.1 2.2 filea fileb


joins filea  and fileb which  have fields separated  by the colon
(`:') character.  The join field number  is 3 for filea and 1 (by
default) for fileb.  The selected five fields are produced in the
output.



COHERENT Lexicon                                           Page 1




join                         Command                         join



***** See Also *****

awk, comm, commands, sort, uniq






















































COHERENT Lexicon                                           Page 2

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