\input texinfo @c -*-texinfo-*-
@c This file uses the @command command introduced in Texinfo 4.0.
@c %**start of header
@setfilename ffe.info
@settitle ffe - flat file extractor
@finalout
@c %**end of header
@include version.texi

@ifinfo
@dircategory Utilities
@direntry
* ffe: (ffe).                 Flat File Extractor.
@end direntry
@end ifinfo


@copying
This file documents version @value{VERSION} of @command{ffe}, a flat file extractor. 

Copyright @copyright{} 2007 Timo Savinen

@quotation
Permission is granted to make and distribute verbatim copies of
this manual provided the copyright notice and this permission notice
are preserved on all copies.

Permission is granted to copy and distribute modified versions of this
manual under the conditions for verbatim copying, provided that the entire
resulting derived work is distributed under the terms of a permission
notice identical to this one.

Permission is granted to copy and distribute translations of this manual
into another language, under the above conditions for modified versions.
@end quotation
@end copying

@titlepage
@title ffe
@subtitle flat file extractor
@subtitle Version @value{VERSION}, @value{UPDATED}
@author by Timo Savinen

@page
@vskip 0pt plus 1filll
@insertcopying
@end titlepage

@c All the nodes can be updated using the EMACS command
@c texinfo-every-node-update, which is normally bound to C-c C-u C-e.
@ifnottex
@node Top, Overview, (dir), (dir)
@top ffe

@insertcopying
@end ifnottex


@c All the menus can be updated with the EMACS command
@c texinfo-all-menus-update, which is normally bound to C-c C-u C-a.
@menu
* Overview::                    Preliminary information.
* Samples::                     Samples using @command{ffe}.
* Invoking ffe::                How to run @command{ffe}.
* ffe configuration::           How @command{ffe} works.
* Problems::                    Reporting bugs.
@end menu

@node Overview, Samples, Top, Top
@chapter Preliminary information
@cindex greetings
@cindex overview

The @command{ffe} program is a used to extract fields from flat files and to print them in different
formats. The input file structure and printing definitions are defined in a configuration file, which
is always required. Default configuration file is @file{~/.fferc} (@file{ffe.rc} in windows).

@command{ffe} is a command line tool developed for GNU/Linux and UNIX systems. @command{ffe} can read from
standard input and write to standard output, so it can be used as a part of a pipeline.

There is also binary distribution for windows.

@node Samples, Invoking ffe, Overview, Top
@chapter Samples using @command{ffe}
@cindex sample

One example of using @command{ffe} for printing personnel information in XML format from fixed length flat file:

@example
$ cat personnel
john     Ripper       23
Scott    Tiger        45
Mary     Moore        41
$
@end example

@noindent
A file @file{personnel} contains three fixed length fields: @samp{FirstName}, @samp{LastName} and @samp{Age},
their respective lengths are 9,13 and 2.

@noindent
In order to print data above in XML, following configuration file must be available:

@example
$cat personnel.fferc
structure personel @{
    type fixed
    output xml
    record person @{
        field FirstName 9
        field LastName  13
        field Age 2
    @}
@}

output xml @{
    file_header "<?xml version=\"1.0\" encoding=\"ISO-8859-1\"?>\n"
    data "<%n>%t</%n>\n"
    record_header "<%r>\n"
    record_trailer "</%r>\n"
    indent " "
@}
$
@end example

@noindent
Using ffe:

@example
$ffe -c personnel.fferc personnel
<?xml version="1.0" encoding="ISO-8859-1"?>
 <person>
  <FirstName>john</FirstName>
  <LastName>Ripper</LastName>
  <Age>23</Age>
 </person>
 <person>
  <FirstName>Scott</FirstName>
  <LastName>Tiger</LastName>
  <Age>45</Age>
 </person>
 <person>
  <FirstName>Mary</FirstName>
  <LastName>Moore</LastName>
  <Age>41</Age>
 </person>
$
@end example

@node Invoking ffe, ffe configuration, Samples, Top
@chapter How to run @command{ffe}
@cindex running ffe
@cindex using

@command{ffe} is a command line tool. Normally @command{ffe} can be invoked as:

@code{ffe -o OUTPUTFILE INPUTFILE@dots{}}

@noindent
@command{ffe} uses the definitions from configuration file and tries to guess the input file
structure using the first 10 000 lines or 1 MB of input data. 

@noindent
If the structure cannot be guessed the option @option{-s} must be used.

@menu
* Invocation::      Program invocation
* Configuration::   Input and printing definitions
* Guessing::        How ffe identifies input structure
* Limits::          Limitations
@end menu

@node Invocation, Configuration, , Invoking ffe
@section Program invocation
@cindex options

@noindent
The format for running the @command{ffe} program is:

@example
ffe @var{option} @dots{}
@end example

@noindent
@command{ffe} supports the following options:

@c Formatting copied from the Texinfo 4.0 manual.
@table @code
@item -c @var{file}
@itemx --configuration=@var{file}
Configuration is read from @var{file}, instead of @file{~/.fferc} (@file{ffe.rc} in windows).

@item -s @var{structure}
@itemx --structure=@var{structure}
Use structure @var{structure} for input file, suppresses guessing.

@item -p @var{output}
@itemx --print=@var{output}
Use output format @var{output} for printing. If not defined, then the record or structure related
output format is used. Printing can be suppressed using format @var{no}. 

@item -o @var{file}
@itemx --output=@var{file}
Write output to @var{file} instead of standard output.

@item -f @var{list}
@itemx --field-list=@var{list}
Print only fields and constants expresses in comma separated list @var{list}. Order of names in 
@var{list} defines also the printing order.

@item -e @var{expression}
@itemx --expression=@var{expression}
Print only those records for which the @var{expression} evaluates to true.

@item -a
@itemx --and
Expressions are combined with logical and, default is logical or.

@item -v
@itemx --invert-match
Print only those records which don't match the expression.

@item -l
@itemx --loose
Normally @command{ffe} stops when it encounters an input line which doesn't match any of
the records in selected structure. Defining this option causes @command{ffe} continue despite the error.

@item -r
@itemx --replace=@var{field}=@var{value}
Replace @var{field}s contents with @var{value} in output. @var{value} can contain same directives as output option @code{data}.

@item -?
@itemx --help
Print an informative help message describing the options and then exit
successfully.

@item -V
@itemx --version
Print the version number of @command{ffe} and then exit successfully.
@end table

All remaining options are names of input files, if no input files are specified or @code{-} is given, then the standard input is read.

@subheading Expressions (option @option{-e}, @option{--expression})
Expression can be used to select specific records comparing field values. 
Expression has syntax @var{field}@strong{x}@var{value}, where @strong{x} is the comparison operator.
Expression is used to compare field's contents to @var{value} and if comparison is successful
the record is printed. Several expressions can be defined and at least one must evaluate to true in
order to print a record. If option @option{-a} is defined all expressions must evaluate to true.

@noindent
Expressions can be defined as:

@table @var
@item field@strong{=}value
Field @var{field} is equal to @var{value}.

@item field@strong{^}value
Field @var{field} starts with @var{value}.

@item field@strong{~}value
Field @var{field} contains @var{value}.

@item field@strong{!}value
Field @var{field} is not equal to @var{value}.

@item field@strong{?}value
Field @var{field} matches the regular expression @var{value}. 
@command{ffe} supports POSIX extended regular expressions. 
@end table

@node Configuration, Guessing, Invocation, Invoking ffe
@section Configuration
@cindex configuration

@command{ffe} uses a configuration file in order to read the input file and print the output.

Configuration file for @command{ffe} is a text file. The file may contain empty lines. 
Commands are case sensitive. Comments  begin with the @code{#}-character and end at the end of the line. 
The @code{string} definitions can be enclosed in double quotation @code{"} characters. 
@code{char} is a single character. @code{string} and @code{char} can contain following escape codes: 
@code{\a}, @code{\b}, @code{\t}, @code{\n}, @code{\v}, @code{\f}, @code{\r}, @code{\"} and @code{\#}. 
A backslash can be escaped as @code{\\}.

Configuration has two main parts: the structure, which defines the input file structure and 
the output, which defines how the input data is formatted for output.

@subheading Common syntax
Common syntax for configuration file is:

@example
#comment
const @var{name} @var{value}
@dots{}
structure @var{name} @{
    @i{option value} @dots{}
    @dots{}
    record @var{name} @{
        @i{option value} @dots{}
        @dots{}
    @}
    record @var{name} @{
        @i{option value} @dots{}
        @dots{}
    @}
    @dots{}
@}
structure @var{name} @{
    @dots{}
@}
@dots{}
output @var{name} @{
    @i{option value} @dots{}
    @dots{}
@}
output @var{name} @{
    @dots{}
@}
@dots{}
lookup @var{name} @{
    @i{option value} @dots{}
    @dots{}
@}
lookup @var{name} @{
    @dots{}
@}

@dots{}
@end example

@subheading Structure
Keyword @code{structure} is used to define an input file content. An input file can contain several
types of records (or lines). E.g. file can have a header, data and trailer record types. Records
must be distinguishable from each other, this can be achieved defining different 'keys' 
(@code{id} in record definition) or having different line lengths (for fixed length structure) or different count
of fields (for separated structure) for different records.

@noindent
Typically a @code{structure} maps to a file and a @code{records} maps to a line in the file.

@noindent
A structure is defined as:
@*

@example
structure @var{name} @{
    @i{option value} @dots{}
    @dots{}
@}
@end example

@noindent
A structure can contain following options:

@table @code
@item type fixed|separated [@var{char}] [*]
The fields in the input are fixed length fields or separated by @var{char}. If * is  defined,
multiple sequential separators are considered as one. Default separator is comma.

@item quoted [@var{char}]
Fields may be quoted with char, default quotation mark is double quotation mark '"'.
A quotation mark is assumed be escaped as \@var{char} or doubling the mark as @var{charchar} in input.
Non escaped quotation marks are not preserved in output.

@item header first|all|no
Controls the occurrence of the header line. Default is no. If set as @emph{first} or @emph{all}, the first line
of the first input file is considered as header line containing the names of  the  fields. @emph{first}
means  that  only  the  first  file  has  a header, @emph{all} means means that all files have a header,
all though the names are still taken from the header of the first file. Header line is handled
according the record definition, meaning that the name positions, separators etc. are the same as
for fields.

@item output @var{name}
All records belonging this structure are printed according output format name.
Default is to use output named as @samp{default}.

@item record @var{name} @{@i{options} @dots{}@}
Defines one record for a structure. A structure can contain several record types.
@end table

@subheading Record
A record defines one type of input line in a file. Different records can be distinguished using 
the @code{id} option or different line lengths or field counts. 

@noindent
A record is defined as:
@*

@example
record @var{name} @{
    @i{option value} @dots{}
    @dots{}
@}
@end example
@noindent
A record can contain following options:

@table @code
@item id @var{position} @var{string}
Identifies a record in the input file. Records are identified by the string in input record position
@var{position}. For fixed length input the position is the byte position of input record and for
separated input the position is the @var{position}'th field of the input record. Positions start from one.

A record definition can contain several id's, then all id's must match the input line 
(@code{id}'s are @emph{and-ed}).

@item field @var{name}|FILLER|* [@var{length}]|* [@var{lookup}]
Defines  one  field  in  input  structure.  @var{length} is mandatory for fixed length input structure.
Length is also used for printing the fields in fixed length format (directive @code{%D} in output definitions).

If @emph{*} is defined instead of the name, then the @var{name} will be the ordinal number of the field,
or if the @code{header} option has value @emph{first} or @emph{all}, then the name of the field will taken from
the header line (first line of the input).

If field is named as @code{FILLER}, the field will not appear in output.

If @var{lookup} is defined the fields contents is used to make a lookup in lookup table @var{lookup}. 
If @var{length} is not needed (separated format) but lookup is needed, use asterisk (*) in place of length definition.

The order of fields in configuration file is essential, it defines the field order in a record.
@item fields-from @var{record}
Fields for this record are the same as for record @var{record}. @code{field} and @code{fields-from} are mutually
exclusive.
@item output @var{name}
This record is printed according output format @var{name}. Default is to use output format defined in structure.
@end table

@subheading Output
Keyword @code{output} defines one output format for formatting the flat file data. Formatting
is controlled using options and printf style directives. An output definition is all ways independent
from structure, so one output format can be used with different input file formats.

@noindent
A output is defined as:
@*

@example
output @var{name} @{
    @i{option value} @dots{}
    @dots{}
@}
@end example
@noindent

Actual formatting and printing is controlled using @emph{pictures} in output options. Pictures can contain
following printf style directives:

@table @code
@item %f
Name of the input file.
@item %s
Name of the current structure.
@item %r
Name of the current record.
@item %o
Input record number in current file.
@item %O
Input record number starting from the first file.
@item %n
Field name.
@item %t
Field contents, without leading and trailing whitespaces.
@item %d
Field contents.
@item %D
Field contents, right padded to the field length (requires length definition for the field).
@item %l
Lookup value which has been found using current field as a search key.
@item %L
Lookup value, right padded to the field length.
@item %p
Fields start position in a record. For fixed structure this is field's byte position in the input line
and for separated structure this is the ordinal number of the field. Starts from one.
@item %e
Does not print anything, causes still the "field empty" check to be performed.
Can be  used  when only the names of non-empty fields should be printed.
@item %%
Percent sign.
@end table

@noindent
Output options:
@table @code
@item file_header @var{picture}
@var{picture} is printed once before file contents.
@item file_trailer @var{picture}
@var{picture} is printed once after file contents.
@item header @var{picture}
If defined, then the header line describing the field names is printed before records.
Every field name is printed according the @var{picture} using the same separator and fields length as
defined for the fields. Picture can contain only @code{%n} directive.
@item data @var{picture}
Field contents is printed according @var{picture}.
@item lookup @var{picture}
If current field is related to lookup table, then this @var{picture} is used instead of picture from @code{data}.
This makes possible to use different picture when the field is related to a lookup table. Default is to use the picture from @code{data}.
@item separator @var{string}
All fields are terminated by @var{string}, except the last field of the record.
Default is not to print separator.
@item record_header @var{picture}
All records are started by @var{picture}. Default is not to print the record header.
@item record_trailer @var{picture} 
All records are ended with @var{picture}. Default is newline.
@item justify left|right|@var{char}
The output from the @code{data} option is left or right justified. 
@var{char} justifies output according the first occurrence of @var{char}
in the data picture. Default is left.
@item indent @var{string}
Record contents is intended by @var{string}. 
Field contents is intended by two times the string. Default is not to indent.
@item field-list @var{name1},@var{name2},@dots{}
Only fields and constants named as @var{name1},@var{name2},@dots{} are printed, same effect as has option @option{-f}. 
Default is print all fields and no constants. Fields and constants are also printed in the same order as they are listed.
@item no-data-print yes|no
If @code{field-list} is defined and and this is set as no and none of the fields in @code{field-list}
does not belong to the current record, then the @code{record_header} and @code{record_trailer} are not printed.
Default is yes.
@item field-empty-print yes|no
When set as no, nothing is printed for fields which consist entirely of characters from @code{empty-chars}. 
If none of the fields of a record are printed, then the printing of @code{record_trailer} is also suppressed. 
Default is yes.
@item empty-chars @var{string}
@var{string} defines a set of characters which define an "empty" field. Default is
@w{" \f\n\r\t\v"} (space, form-feed, newline, carriage return, horizontal tab and vertical tab).
@end table

@subheading Lookup
Keyword @code{lookup} defines a lookup table which can searched using field contents. Found values can
be printed using output directives @code{%l} and @code{%L}.

@noindent
A lookup table is defined as:
@*

@example
lookup @var{name} @{
    @i{option value} @dots{}
    @dots{}
@}
@end example

@noindent
Lookup options:
@table @code
@item search exact | longest
Search method for this table. Either exact or longest match is used when searching the table. Default is @code{exact}.
@item pair @var{key} @var{value}
Defines one key/value pair for the lookup table.
@item file @var{name} [@var{separator}]
Data for the lookup table is read from file @var{name}. Each line in file @var{name} is considered as a key/value pair
separated by a single character @var{separator}. Default separator is semicolon. Lines without separator are silently omitted.
@strong{Note}: File size is limited by available memory because the file contents is loaded to memory. 
@item default-value @var{value}
If searching the lookup table is unsuccessful then @var{value} is used in printing. Default is empty string.
@end table

@subheading Constants
Keyword @code{const} defines one name/value pair which can be used as an additional output field.
Constants can be used only in field lists (option @option{-f,--field-list}, or output option @code{field-list}).

Constants can be used to add fields to output which do not appear in input. E.g. new fields for 
separated output or adding spaces after a fixed length field (changing the field length).

Note that @var{value} is printed as it is for every record. It cannot be changed record by record.

If a constant has the same name as one of the input fields, the value @var{value} is printed instead of
the input field contents.

A constant is defined as:
@*

@example
const @var{name} @var{value}
@end example

When @var{name} appears in field list it is treated as one of the input fields having contents @var{value}.

@node Guessing,Limits,Configuration,Invoking ffe
@section Guessing
@cindex guess
If @option{-s} is not given, @command{ffe} tries to guess the input structure. 
@command{ffe} reads first 10 000 lines or 1 MB of input data and tries to match the structure definitions
from configuration file to input stream. If all lines match one and only one structure, the structure is used
for reading the input file.

@noindent
Guessing uses following execution cycle:

@enumerate
@item 
Input line is read
@item
All record @code{id}'s are compared to the input line, if all @code{id}'s of a record match 
the input line and the
records line length matches the total length (or total count for separated structure) of the fields,
the record is considered to match the input line. If there are no @code{id}'s, 
only the line length or field count is checked.
@item
If all lines match at least one of the records in a particular structure, the structure is considered as selected. 
There must be only one structure matching all lines used for guessing.
@end enumerate


@node Limits, , Guessing, Invoking ffe
@section Limitations
@cindex big files
@cindex limits

At least in GNU/Linux @command{ffe} should be able to handle big files (> 4 GB), other
systems are  not tested.

Regular expression can be used in expressions (operator @strong{?} in option @option{-e}, @option{--expression}) only in systems where
regular expression functions (regcomp, regexec, @dots{}) are available.

@node ffe configuration, Problems, Invoking ffe, Top
@chapter How @command{ffe} works
Following examples use two different input files: 
@subheading Fixed length example
Fixed length personnel file with header and trailer, line (record) is identified by the
first byte (H = Header, E = Employee, B = Boss, T = trailer).
@example
$cat personnel.fix
H2006-02-25
EJohn     Ripper       23
BScott    Tiger        45
EMary     Moore        41
ERidge    Forrester    31
T0004
$
@end example

@noindent
Structure for reading file above. Note that record @samp{boss} reuses fields from @samp{employee}.

@example
structure personel_fix @{
    type fixed
    record header @{
        id 1 H
        field type 1
        field date 10
    @}
    record employee @{
        id 1 E
        field EmpType 1
        field FirstName 9
        field LastName  13
        field Age 2
    @}
    record boss @{
        id 1 B
        fields-from employee
    @}
    record trailer @{
        id 1 T
        field type 1
        field count 4
    @}
@}
@end example

@subheading Separated example
Same file as above, but now separated by colon.

@example
$cat personnel.sep
H,2006-02-25
E,john,Ripper,23
B,Scott,Tiger,45
E,Mary,Moore,41
E,Ridge,Forrester,31
T,0004
$
@end example

@noindent
Structure for reading file above. Note that the field lengths are not needed in separated format.

@example
structure personel_sep @{
    type separated ,
    record header @{
        id 1 H
        field type 
        field date 
    @}
    record employee @{
        id 1 E
        field type 
        field FirstName 
        field LastName 
        field Age 
    @}
    record boss @{
        id 1 B
        fields-from employee
    @}
    record trailer @{
        id 1 T
        field type 
        field count
    @}
@}
@end example

@subheading Printing in XML format
Data in examples above can be printed in XML using output definition like:

@example
output xml @{
    file_header "<?xml version=\"1.0\" encoding=\"UTF-8\"?>\n"
    data "<%n>%t</%n>\n"
    record_header "<%r>\n"
    record_trailer "</%r>\n"
    indent " "
@}
@end example

@noindent
Example output using command (assuming definitions above are saved in ~/.fferc)

@code{ffe -p xml personnel.sep}

@example
<?xml version="1.0" encoding="UTF-8"?>
 <header>
  <type>H</type>
  <date>2006-02-25</date>
 </header>
 <employee>
  <type>E</type>
  <FirstName>john</FirstName>
  <LastName>Ripper</LastName>
  <Age>23</Age>
 </employee>
 <boss>
  <type>B</type>
  <FirstName>Scott</FirstName>
  <LastName>Tiger</LastName>
  <Age>45</Age>
 </boss>
 <employee>
  <type>E</type>
  <FirstName>Mary</FirstName>
  <LastName>Moore</LastName>
  <Age>41</Age>
 </employee>
 <employee>
  <type>E</type>
  <FirstName>Ridge</FirstName>
  <LastName>Forrester</LastName>
  <Age>31</Age>
 </employee>
 <trailer>
  <type>T</type>
  <count>0004</count>
 </trailer>
@end example
@subheading Printing sql commands
Data in examples above can be loaded to database by generated sql commands. Note that the header and trailer
are not loaded, because only fields @samp{FirstName},@samp{LastName} and @samp{Age} are printed and @samp{no-data-print}
is set as no. This prevents the @samp{record_header} and @samp{record_trailer} to be printed for file header and trailer.

@example
output sql @{
    file_header "delete table boss;\ndelete table employee;\n"
    record_header "insert into %r values("
    data "'%t'"
    separator ","
    record_trailer ");\n"
    file_trailer "commit\nquit\n"
    no-data-print no
    field-list FirstName,LastName,Age
@}
@end example

@noindent
Output from command

@code{ffe -p sql personnel.sep}

@example
delete table boss;
delete table employee;
insert into employee values('john','Ripper','23');
insert into boss values('Scott','Tiger','45');
insert into employee values('Mary','Moore','41');
insert into employee values('Ridge','Forrester','31');
commit
quit
@end example
@subheading Human readable output
This output format shows the fields suitable for displaying in screen or printing.

@example
output nice @{
    record_header "%s - %r - %f - %o\n"
    data "%n=%t\n"
    justify =
    indent " "
@}
@end example

@noindent
Output from command

@code{ffe -p nice personnel.fix}
@example
 personel - header - personnel.fix - 1
  type=H
  date=2006-02-25
 
 personel - employee - personnel.fix - 2
    EmpType=E
  FirstName=John
   LastName=Ripper
        Age=23
 
 personel - boss - personnel.fix - 3
    EmpType=B
  FirstName=Scott
   LastName=Tiger
        Age=45
 
 personel - employee - personnel.fix - 4
    EmpType=E
  FirstName=Mary
   LastName=Moore
        Age=41
 
 personel - employee - personnel.fix - 5
    EmpType=E
  FirstName=Ridge
   LastName=Forrester
        Age=31
 
 personel - trailer - personnel.fix - 6
   type=T
  count=0004
@end example

@subheading HTML table
Personnel data can be displayed as HTML table using output like:

@example
output html @{
    file_header "<html>\n<head>\n</head>\n<body>\n<table border=\"1\">\n<tr>\n"
    header "<th>%n</th>\n"
    record_header "<tr>\n"
    data "<td>%t</td>\n"
    file_trailer "</table>\n</body>\n</html>\n"
    no-data-print no
@}
@end example

@noindent
Output from command

@code{ffe -p html -f FirstName,LastName,Age personnel.fix}
@example
<html>
<head>
</head>
<body>
<table border="1">
<tr>
<th>FirstName</th>
<th>LastName</th>
<th>Age</th>

<tr>
<td>John</td>
<td>Ripper</td>
<td>23</td>

<tr>
<td>Scott</td>
<td>Tiger</td>
<td>45</td>

<tr>
<td>Mary</td>
<td>Moore</td>
<td>41</td>

<tr>
<td>Ridge</td>
<td>Forrester</td>
<td>31</td>

</table>
</body>
</html>
@end example

@subheading Using expression
Printing only Scott's record using expression with previous example:

@code{ffe -p html -f FirstName,LastName,Age -e FirstName^Scott personnel.fix}
@example
<html>
<head>
</head>
<body>
<table border="1">
<tr>
<th>FirstName</th>
<th>LastName</th>
<th>Age</th>

<tr>
<td>Scott</td>
<td>Tiger</td>
<td>45</td>

</table>
</body>
</html>
@end example

@subheading Using replace
Make all bosses and write a new personnel file printing the fields in fixed length format
using directive @code{%D}:

@noindent
Output definition:
@example
output fixed 
@{
    data "%D"
@}
@end example

@noindent
Write a new file:
@example
$ffe -p fixed -r EmpType=B -o personnel.fix.new personnel.fix
$cat personnel.fix.new
H2006-02-25
BJohn     Ripper       23
BScott    Tiger        45
BMary     Moore        41
BRidge    Forrester    31
T0004
$
@end example

@subheading Using constant
The length of the fields FirstName and LastName in fixed length format will be made two bytes longer.
This will be done by printing a constant after those two fields.
We use dots instead of spaces in order to make change more visible.

Because we do not want to change header and trailer we need specially crafted configuration file. 
Employee and boss records will be printed using new output @var{fixed2} and other records will be printed using 
output @var{default}.

New definition file @file{new_fixed.rc}:
@example
const 2dots ".."

structure personel_fix @{
    type fixed
    record header @{
        id 1 H 
        field type 1 
        field date 10
    @}
    record employee @{
        id 1 E
        field EmpType 1 
        field FirstName 9
        field LastName  13
        field Age 2
        output fixed2
    @}
    record boss @{
        id 1 B
        fields-from employee
        output fixed2
    @}
    record trailer @{
        id 1 T
        field type 1 
        field count 4
    @}
@}

output default
@{
    data "%D"
@}

output fixed2
@{
    data "%D"
    field-list Emptype,FirstName,2dots,LastName,2dots,Age
@}
@end example
@noindent
Print new flat file:
@example
$ ffe -c new_fixed.rc personel_fix
H2006-02-25
EJohn     ..Ripper       ..23
BScott    ..Tiger        ..45
EMary     ..Moore        ..41
ERidge    ..Forrester    ..31
T0004
$
@end example

@subheading Using lookup table
Lookup table is used to explain the EmpTypes contents in output format @code{nice}:

@noindent
Lookup definition:
@example
lookup Type
@{
    search exact
    pair H Header
    pair B "He is a Boss!"
    pair E "Not a Boss!"
    pair T Trailer
    default-value "Unknown record type!"
@}   
@end example
@noindent
Mapping the EmpType field to lookup:
@example
structure personel_fix @{
    type fixed
    record header @{
        id 1 H
        field type 1
        field date 10
    @}
    record employee @{
        id 1 E
        field EmpType 1 Type
        field FirstName 9
        field LastName  13
        field Age 2
    @}
    record boss @{
        id 1 B
        fields-from employee
    @}
    record trailer @{
        id 1 T
        field type 1
        field count 4
    @}
@}
@end example
@noindent
Adding the lookup option to output definition @code{nice}.
@example
output nice @{
    record_header "%s - %r - %f - %o\n"
    data "%n=%t\n"
    lookup "%n=%t (%l)\n"
    justify =
    indent " "
@}
@end example
@noindent
Running ffe:
@example
 $ffe -p nice personnel.fix
 personel_fix - header - personel_fix - 1
  type=H
  date=2006-02-25
 
 personel_fix - employee - personel_fix - 2
    EmpType=E (Not a Boss!)
  FirstName=John
   LastName=Ripper
        Age=23
 
 personel_fix - boss - personel_fix - 3
    EmpType=B (He is a Boss!)
  FirstName=Scott
   LastName=Tiger
        Age=45
 
 personel_fix - employee - personel_fix - 4
    EmpType=E (Not a Boss!)
  FirstName=Mary
   LastName=Moore
        Age=41
 
 personel_fix - employee - personel_fix - 5
    EmpType=E (Not a Boss!)
  FirstName=Ridge
   LastName=Forrester
        Age=31
 
 personel_fix - trailer - personel_fix - 6
   type=T
  count=0004
@end example

@subheading External lookup file
In previous example the lookup data could be read from external file like:

@example
$cat lookupdata
H;Header
B;He is a Boss!
E;Not a Boss!
T;Trailer
$
@end example
@noindent
Lookup definition using file above:
@example
lookup Type
@{
    search exact
    file lookupdata
    default-value "Unknown record type!"
@}
@end example


@subheading The whole configuration file used in examples
@example
structure personel_fix @{
    type fixed
    record header @{
        id 1 H
        field type 1
        field date 10
    @}
    record employee @{
        id 1 E
        field EmpType 1 Type
        field FirstName 9
        field LastName  13
        field Age 2
    @}
    record boss @{
        id 1 B
        fields-from employee
    @}
    record trailer @{
        id 1 T
        field type 1
        field count 4
    @}
@}

structure personel_sep @{
    type separated ,
    record header @{
        id 1 H
        field type 
        field date 
    @}
    record employee @{
        id 1 E
        field type 
        field FirstName 
        field LastName  
        field Age 
    @}
    record boss @{
        id 1 B
        fields-from employee
    @}
        record trailer @{
        id 1 T
        field type 
        field count
    @}
@}

output xml @{
    file_header "<?xml version=\"1.0\" encoding=\"UTF-8\"?>\n"
    data "<%n>%t</%n>\n"
    record_header "<%r>\n"
    record_trailer "</%r>\n"
    indent " "
@}

output sql @{
    file_header "delete table boss;\ndelete table employee;\n"
    record_header "insert into %r values("
    data "'%t'"
    separator ","
    record_trailer ");\n"
    file_trailer "commit\nquit\n"
    no-data-print no
    field-list FirstName,LastName,Age
@}

output nice @{
    record_header "%s - %r - %f - %o\n"
    data "%n=%t\n"
    lookup "%n=%t (%l)\n"
    justify =
    indent " "
@}

output html @{
    file_header "<html>\n<head>\n</head>\n<body>\n<table border=\"1\">\n<tr>\n"
    header "<th>%n</th>\n"
    record_header "<tr>\n"
    data "<td>%t</td>\n"
    file_trailer "</table>\n</body>\n</html>\n"
    no-data-print no
@}

output fixed 
@{
    data "%D"
@}

lookup Type
@{
    search exact
    pair H Header
    pair B "He is a Boss!"
    pair E "Not a Boss!"
    pair T Trailer
    default-value "Unknown record type!"
@}   
@end example

@subheading Using @command{ffe} to test file integrity
@command{ffe} can be used to check flat file integrity, because @command{ffe} 
checks for all lines the line length and id's for fixed length structure 
and field count and id's for separated structure.

@noindent
Integrity can be checked using command 

@code{ffe -p no -l inputfiles@dots{}}

@noindent
Because option @option{-p} has value @code{no} nothing is printed to output except the error messages.
Option @option{-l} causes all erroneous lines to be reported, not just the first one.

@noindent
Example output:

@example
ffe: Invalid input line in file 'inputfileB', line 14550
ffe: Invalid input line in file 'inputfileD', line 12
@end example

@node Problems, , ffe configuration, Top
@chapter Reporting Bugs
@cindex bugs
@cindex problems

If you find a bug in @command{ffe}, please send electronic mail to
@email{tjsa@@iki.fi}.  Include the version number, which you can find by
running @w{@samp{ffe --version}}.  Also include in your message the
output that the program produced and the output you expected.@refill

If you have other questions, comments or suggestions about
@command{ffe}, contact the author via electronic mail to
@email{tjsa@@iki.fi}.  The author will try to help you out, although he
may not have time to fix your problems.

@contents
@bye