dmerge(USP)

Name

dmerge : Merges files based on a key

Synopsis

Usage   : dmerge key=<pos> <file1> <file2> ..

Options : -e

          -s<c>

Version : Tue Jan  9 09:02:34 JST 2024

Edition : 3

Description

Merges the specified files <file1> <file2>... based on the key

field specified as key=<pos>. Each file must already be sorted

on the specified field.  <key> designates the field position as

fllows:

single field       2        the 2nd field

                   NF   the last field

                   NF-1   the field just before the last field

contiguous fields  2/4      from the 2nd field to the 4th field

                   4/2   from the 4th field to the 2nd field

                   NF-3/NF  from NF-3 field to the NF field

combination        2@NF     the 2nd field and the NF field

There is no limit on the length of the key field or on the number

of key fields.  The key field can also contain multi-byte characters

such as Japanese.

If you specify "r" as comparison method after the field position,

the fields are compared in reverse order.  If you specify "n" as

comparison method after the field position, that field's values will

be compared as numbers.  If you specify "nr" as comparison method

after the field, the values will be compared in reverse order as

numbers.  If you specify comparison method before or after the "/",

you must use the same comparison method for both fields.

  2n/5n     OK

  2n/5nr    Error

  2n/5r     Error

When you specify "e" as comparison method or specify -e ootion and no

method, characters in the field are replaced as follows and compared

as string:

  _  ==> 0x20 (space)

  \0 ==> 0x00 (null)

  \t ==> 0x09 (tab stop)

  \n ==> 0x0a (new line)

  \r ==> 0x0d (carrige return)

  \_ ==> 0x5f (underscore)

  \\ ==> 0x5c (back slash)

Example 1

Merge three files on the first field (files are sorted on this field).

$ cat file1

A 1

A 2

B 1

B 2

$ cat file2

A 3

A 4

B 3

B 4

$ cat file3

B 5

B 6

C 1

C 2

Merge file1, file2 and file3.

The order of the records in file1, file2 and file3 is not defined.

$ dmerge key=1 file1 file2 file3

A 1

A 2

A 3

A 4

B 3

B 4

B 5

B 6

B 1

B 2

C 1

C 2