underlay(USP)

Name

underlay : Overlay fields one record at a time.

Synopsis

Usage   : underlay [key=<key>] <file>

          underlay num=<n> <file>

Options : -a

          -d<str>

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

Edition : 2

Description

Using the fields specified by <key> as key fields, overlay in order

each field in records that contain the same key. <key> designates

the field position as fllows:

single field       TAGa       TAGa field

contiguous fields  TAGa/TAGb from TAGa field to TAGb field

combination        TAGa@TAGb  TAGa field and TAGb 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.

The tag name specfying the field can be eclosed by braces {}.  In

this case, tag names can include special charcter like "/" or "@".

Moreover, tag names can include pairs of braces.

The "@" character is the NULL character by default; fields that

contain this value are not overlaid.  Use option -d to change

the NULL character.

The last records of blocks are written to output. If -a option

is specfied, all records are written to output.

If <file> is not specified or specified as "-" then the command

reads from standard input.

Example 1

$ cat data

001 001 001 a b c

001 001 001 @ B @

002 002 002 @ e _

002 002 002 d E f

002 002 002 @ @ F

003 003 003 g h i

003 003 003 _ H @

The default NULL character is "@".

$ underlay num=3 data

001 001 001 a B c

002 002 002 d E F

003 003 003 _ H i

Example 2

Change the NULL character to "_".

$ underlay -d_ num=3 data

001 001 001 @ B @

002 002 002 @ @ F

003 003 003 g H @

Example 3

Specify multiple NULL characters.

$ underlay -d_ -d@ num=3 data

001 001 001 a B c

002 002 002 d E F

003 003 003 g H i

Example 4

If you specify num=0 then there is no key and all fields

are overlaid.

$ underlay num=0 data

003 003 003 _ H i

Example 5

All records are written when -a option specified.

$ underlay -a num=3 data

001 001 001 a b c

001 001 001 a B c

002 002 002 @ e _

002 002 002 d E f

002 002 002 d E F

003 003 003 g h i

003 003 003 _ H i