ffe: add page (#6261)

* ffe: add page

* ffe: changes following review comments

- Clarified required default or specific configuration
  - Added .ffe to path/to/config.ffe
  - Mentioned ~/fferc in --structure --print example
- Using long-format flags. Short format -c used for later samples
- Fixed case of LastNAme in sample format of --filed-list

* ffe: fix missing braces. oops.

* ffe: add back-quotes and period missing from `~/.fferc`

* ffe: Use Cobra_Case for field names in sample field-list as requested.

* ffe: Accept suggested "A configuration file is required"

* ffe: Change sample --field-list value back to author's CamelCase, as requested.

pages/common/ffe.md

@@ -0,0 +1,29 @@
+# ffe
+
+> Extract fields from a flat database file and write to another format.
+> A configuration file is required to interpret the input and format the output.
+> More information: <http://ff-extractor.sourceforge.net/ffe.html>.
+
+- Display all input data using the specified data configuration:
+
+`ffe --configuration={{path/to/config.ffe}} {{path/to/input}}`
+
+- Convert an input file to an output file in a new format:
+
+`ffe --output={{path/to/output}} -c {{path/to/config.ffe}} {{path/to/input}}`
+
+- Select input structure and print format from definitions in `~/.fferc` config file:
+
+`ffe --structure={{structure}} --print={{format}} {{path/to/input}}`
+
+- Write only the selected fields:
+
+`ffe --field-list="{{FirstName,LastName,Age}}" -c {{path/to/config.ffe}} {{path/to/input}}`
+
+- Write only the records that match an expression:
+
+`ffe -e "{{LastName=Smith}}" -c {{path/to/config.ffe}} {{path/to/input}}`
+
+- Display help:
+
+`ffe --help`