OSF

NAME

join − Joins the lines of two files

SYNOPSIS

join [-anumber] [-e string] [-j][number][field] [-o number.field ...] [-tcharacter]
file1 file2

The join command reads file1 and file2 and joins lines in the files that contain common fields, or otherwise according to the flags, and writes the results to standard output. 

FLAGS

-anumber
Produces an output line for each line found in file1 if number is 1, or file2 if number is 2.  Without -a, join produces output only for lines containing a common field. 

-e stringReplaces empty output fields with string. 

-j[number]  field
Joins the two files on field of file number, where number is 1 for file1 or 2 for file2.  If you do not specify number, join uses field in each file.  Without -j, join uses the first field in each file. 

-o file.field ...
Produces output lines consisting of the fields specified in one or more number.field arguments, where number is 1 for file1 or 2 for file2, and field is a field number. 

-tcharacter
Uses character (a single character) as the field separator character in the input and the output.  Every appearance of character in a line is significant.  The default separator is a space.  If you do not specify -t, join also recognizes the tab and newline characters as separators.  With default field separation, the collating sequence is that of sort -b.  If you specify -t, the sequence is that of a plain sort.  To specify a tab character, enclose it in ’ ’ (single quotes). 

DESCRIPTION

The join field is the field in the input files that join looks at to determine what will be included in the output.  One line appears in the output for each identical join field appearing in both file1 and file2.  The output line consists of the join field, the rest of the line from file1, then the rest of the line from file2. 

You can specify standard input in place of file1 by substituting a - (dash) for the name. 

Both input files must be sorted according to the collating sequence specified by the LC_COLLATE environment variable, if set, for the fields on which they are to be joined (usually the first field in each line). 

Fields are normally separated by a space, a tab character, or a newline character.  In this case, join treats consecutive separators as one, and discards leading separators.  Use the -t flag to specify another field separator. 

EXAMPLES

Note that the vertical alignment shown in these examples may not be consistent with your output. 

     1.To perform a simple join operation on two files, phonedir and names, whose first fields are the same, enter:

join  phonedir  names

If phonedir contains the following telephone directory:

Binst555-6235
Dickerson555-1842
Eisner555-1234
Green555-2240
Hrarii555-0256
Janatha555-7358
Lewis555-3237
Takata555-5341
Wozni555-1234

and names is this listing of names and department numbers:

EisnerDept. 389
FrostDept. 217
GreenDept. 311
TakataDept. 454
WozniDept. 520

then join phonedir names displays:

Eisner555-1234Dept. 389
Green555-2240Dept. 311
Takata555-5341Dept. 454
Wozni555-1234Dept. 520

Each line consists of the join field (the last name), followed by the rest of the line found in phonedir and the rest of the line in names. 

     2.To display unmatched lines as well as matched line, enter:

join  -a2  phonedir  names

If phonedir contains:

Binst555-6235
Dickerson555-1842
Eisner555-1234
Green555-2240
Hrarii555-0256
Janatha555-7358
Lewis555-3237
Takata555-5341
Wozni555-1234

and names contains:

EisnerDept. 389
FrostDept. 217
GreenDept. 311
TakataDept. 454
WozniDept. 520

then join -a2 phonedir names displays:

Eisner555-1234Dept. 389
FrostDept. 217
Green555-2240Dept. 311
Takata555-5341Dept. 454
Wozni555-1234Dept. 520

This performs the same join operation as in the first example, and also lists the lines of names that have no match in phonedir.  It includes Frost’s name and department number in the listing, although there is no entry for Frost in phonedir. 

     3.To display selected fields, enter:

join  -o 2.3 2.1 1.2 phonedir names

This displays the following fields: Field 3 of names (Department Number) Field 1 of names (Last Name) Field 2 of phonedir (Telephone Number) If phonedir contains:

Binst555-6235
Dickerson555-1842
Eisner555-1234
Green555-2240
Hrarii555-0256
Janatha555-7358
Lewis555-3237
Takata555-5341
Wozni555-1234

and names contains:

EisnerDept. 389
FrostDept. 217
GreenDept. 311
TakataDept. 454
WozniDept. 520

then join -o 2.3 2.1 1.2 phonedir names displays:

389 Eisner555-1234
311 Green555-2240
454 Takata555-5341
520 Wozni555-1234

     4.To perform the join operation on a field other than the first, enter:

sort -b +1 -2 phonedir | join -j1 2 - numbers

This combines the lines in phonedir and names, comparing the second field of phonedir to the first field of numbers.  First, this sorts phonedir by the second field because both files must be sorted by their join fields.  The output of sort is then piped to join.  The - (dash) by itself causes the join command to use this output as its first file.  -j1 2 defines the second field of the sorted phonedir as the join field.  This is compared to the first field of numbers because its join field is not specified with a -j flag.  If phonedir contains:

Binst555-6235
Dickerson555-1842
Eisner555-1234
Green555-2240
Hrarii555-0256
Janatha555-7358
Lewis555-3237
Takata555-5341
Wozni555-1234

and numbers contains:

555-0256
555-1234
555-5555
555-7358

then sort ... | join ... displays:

555-0256Hrarii
555-1234Eisner
555-1234Wozni
555-7358Janatha

Each number in numbers is listed with the name listed in phonedir for that number.  Note that join lists all the matches for a given field.  In this case, join lists both Eisner and Wozni as having the telephone number 555-1234.  The number 555-5555 is not listed because it does not appear in phonedir. 

RELATED INFORMATION

Commands:  awk(1), comm(1), cut(1), paste(1), sort(1). 

OSF/1 User’s Guide.