Frequently, one wants to call a command on the operating system level from SQL-PL. The EXEC command serves this purpose.
Normally, the operating system commands are called synchronously. Some operating systems allow an asynchronous command call, in addition.
For a synchronous call, a program result is returned in any SQL-PL variable. For an asynchronous call, there is no such result.
Examples:
For the synchronous call, there are two additional options that determine whether user interaction is desired or not. Without an option specification, the command executed synchronously must be
confirmed by using the 
key. If the option NOHOLD is specified, the screen is cleared by the synchronous command, but no user input is expected. The option QUIET has the effect that
the synchronous command is performed without any screen and user interaction.
Note:
1. For an asynchronous command or program call, restrictions specific to the operating system must be observed (see the platform-specific User manual).
2. Not every operating system allows foreign programs to be called.
Apart from the EXEC command, operating system commands can be issued and foreign programs be called via the command line at any time.
Examples: under UNIX: EXEC ls -ls > list
EXEC vi sqlpl.prot
Other syntax formats adapted to the operating system concerned are described in the platform-specific User manual.
Syntax:
