In addition to the default output, produce a line for each unpairable line in file file_number.
-e string
Replace empty output fields with string.
-o list
The -o option specifies the fields that will be output from each file for each line with matching join fields. Each element of list has the either the form ‘file_number.field’, where file_number is a file number and field is a field number, or the form ‘0’ (zero), representing the join field. The elements of list must be either comma (‘,’) or whitespace separated. (The latter requires quoting to protect it from the shell, or, a simpler approach is to use multiple -o options.)
-t char
Use character char as a field delimiter for both input and output. Every occurrence of char in a line is significant.
-v file_number
Do not display the default output, but display a line for each unpairable line in file file_number. The options -v 1 and -v 2 may be specified at the same time.
-1 field
Join on the field ’th field of file 1.
-2 field
Join on the field ’th field of file 2.
When the default field delimiter characters are used, the files to be joined should be ordered in the collating sequence of sort(1), using the -b option, on the fields on which they are to be joined, otherwise join may not report all field matches. When the field delimiter characters are specified by the -t option, the collating sequence should be the same as sort(1) without the -b option.
If one of the arguments file1 or file2 is "-", the standard input is used.
In addition to the default output, produce a line for each unpairable line in both file 1 and file 2.
-j1 field
Join on the field ’th field of file 1.
-j2 field
Join on the field ’th field of file 2.
-j field
Join on the field ’th field of both file 1 and file 2.
-o list ...
Historical implementations of join permitted multiple arguments to the -o option. These arguments were of the form ‘file_number.field_number’ as described for the current -o option. This has obvious difficulties in the presence of files named ‘1.2’.
These options are available only so historic shellscripts do not require modification and should not be used.
