Where possible, use standard system commands instead of variants unique to certain hardware manufacturers. The following table lists the OS statements that promote portability by avoiding limitations of operating-system-specific commands. These statements allow you to create a single version of a procedure that works differently on varying operating systems.

Table 1. OS statements
OS statement Description 
OS-APPEND
 Performs a system call to execute the operating system command that appends two files. 
OS-COMMAND
 Performs a system call to execute an operating system command that you specify. 
OS-COPY
 Performs a system call to execute the operating system command that copies a file. 
OS-CREATE-DIR
 Performs a system call to execute the operating system command that creates a new directory. 
OS-DELETE
 Performs a system call to execute the operating system command that deletes a file or directory. You can delete one or more files, a directory, or an entire directory branch. 
OS-DRIVES
 Performs a system call to execute the operating system command that returns a comma-separated list of the available drives in Windows. 
OS-ERROR
 Returns an OpenEdge error code that indicates whether an execution error occurred during the last OS-APPEND, OS-COMMAND, OS-COPY, OS-CREATE-DIR, OS-DELETE, or OS-RENAME statement. 
OS-GETENV
 Performs a system call to execute the operating system command that returns a string containing the value of the specified environment variable in the environment in which OpenEdge is running. 
OS-RENAME
 Performs a system call to execute the operating system command that renames a file or directory.

See the ABL Reference for more information on these statements.