System & Data Manipulation

These commands go beyond simple formatting; they interact with the operating system environment or modify the record structure in memory during execution.

Field Update (proc)

The proc function allows you to append, replace, or delete fields in the current record in memory (virtual update). This is extremely powerful for temporary data manipulation during export or complex processing chains.

• Syntax: proc('CommandString')
• Returns: An empty string (it performs an action, does not display text).

Command String Syntax

The argument is a format that generates a string of commands. The commands are executed sequentially:

1. Delete (d): Must be specified before adding fields.
2. Add (a): Appends a new occurrence.
3. Add with Length (h): Adds a new occurrence with a specific byte length.

Command	Format	Description
Delete All	d*	Deletes all fields in the record.
Delete Tag	dTag	Deletes all occurrences of the specified Tag (e.g., d70).
Delete Occ	dTag/Occ	Deletes a specific occurrence (e.g., d70/1).
Add	aTag#Data#	Adds Data as a new occurrence of Tag. The delimiter (#) can be any non-numeric character.
Add Binary	hTag Len Data	Adds Data of length Len (in bytes) to Tag. Requires a space separator.

Examples

Example 1: Cleaning and restructuring a record Delete all fields and create a new temporary field 1000 with the content of field 10.

proc('d* a1000|'v10'|')

Example 2: Adding a computed field Keep existing data but add a "Timestamp" field (Tag 9000) with the current date.

proc('a9000#' date '#')

Example 3: Conditional Deletion Delete field 24 only if it contains the word "Obsolete".

proc( if v24 : 'Obsolete' then 'd24' fi )

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Environment Variables

ABCD and CISIS rely heavily on environment variables (like CIPAR, PATH, or custom CGI variables).

getenv - Get Variable

Retrieves the value of an operating system environment variable.

• Syntax: getenv('VAR_NAME')
• Example:

"Current Database Path: ", getenv('db_path')

putenv - Set Variable

Sets an environment variable for the current process scope.

• Syntax: putenv('VAR_NAME=VALUE')
• Usage: Useful for passing parameters between nested formats or scripts.
• Example:

putenv('MY_VAR=Active'),
if getenv('MY_VAR') = 'Active' then ... fi

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System Interaction

date - Current Date

Returns the current system date and time.

• Syntax: date
• Format: Typically returns YYYYMMDD h:m:s (e.g., 20231027 14:30:05), but format may vary by OS.
• Example:

"Report generated: " date

system - Execute Command

Executes an external operating system command.

• Syntax: system('Command')
• Returns: The exit code of the command (usually 0 for success).
• Warning: This command pauses the formatting process until the external command finishes.
• Example:

/* Linux: List files in /tmp */
system('ls -l /tmp > filelist.txt')