Editing COBOL (section)

===Environment division===
The environment division contains the configuration section and the input-output section. The configuration section is used to specify variable features such as currency signs, locales and character sets. The input-output section contains file-related information.

====Files====
COBOL supports three file formats, or ''{{dfn|organizations}}'': sequential, indexed and relative. In sequential files, records are contiguous and must be traversed [[sequential access|sequentially]], similarly to a [[linked list]]. Indexed files have one or more indexes which allow records to be [[random access|randomly accessed]] and which can be sorted on them. Each record must have a [[unique key]], but other, ''{{dfn|alternate}}'', record keys need not be unique. Implementations of indexed files vary between vendors, although common implementations, such as [[C-ISAM]] and [[VSAM]], are based on IBM's [[ISAM]]. Other implementations are [[Record Management Services]] on [[OpenVMS]] and [[Enscribe]] on [[NonStop (server computers)|HPE NonStop]] (Tandem). Relative files, like indexed files, have a unique record key, but they do not have alternate keys. A relative record's key is its ordinal position; for example, the 10th record has a key of 10. This means that creating a record with a key of 5 may require the creation of (empty) preceding records. Relative files also allow for both sequential and random access.{{sfn|ISO/IEC JTC 1/SC 22/WG 4|2014|loc=§ D.2.1}}

A common non-standard extension is the ''{{dfn|line sequential}}'' organization, used to process text files. Records in a file are terminated by a [[newline]] and may be of varying length.<ref>{{cite web | url=http://supportline.microfocus.com/documentation/books/nx30books/fhorgs.htm | title=File Organizations | publisher=Micro Focus | work=File Handling | date=1998 | access-date=27 June 2014 | archive-date=4 March 2016 | archive-url=https://web.archive.org/web/20160304091459/http://supportline.microfocus.com/documentation/books/nx30books/fhorgs.htm | url-status=dead }}</ref>