The SPAWN command creates a sub-process of the current process. Format: SPAWN [/qualifiers] [command-string]
1 – Parameters
The command has the following optional parameter. command-string Specifies a command string of up to 131 characters that is to be executed in the context of the created sub-process. When the command completes, the sub-process terminates and control returns to the parent process. If you do not specify a command string, a sub-process is created and remains until you log out.
2 – Command qualifiers
The command has the following qualifiers: /INPUT /LOGICAL_NAMES /OUTPUT /PROCESS_NAME /PROMPT /SYMBOLS /WAIT
3 /INPUT
/INPUT=file-spec Specifies an input file that contains one or more DCL commands to be executed by the spawned sub-process. Once processing of the input file is complete, the sub-process is terminated. If both the command-string parameter and the /INPUT qualifier are specified, the command string is executed before the DCL commands in the file specified by the /INPUT qualifier.
4 /LOGICAL_NAMES
/LOGICAL_NAMES /NOLOGICAL_NAMES Specifies whether process logical names and logical name tables are to be copied to the spawned sub-process. The default is LOGICAL_NAMES.
5 /OUTPUT
/OUTPUT=file-spec Specifies the name of the output file to which the spawned sub-process writes its output. The default is SYS$OUTPUT.
6 /PROCESS_NAME
/PROCESS_NAME=subprocess-name Specifies the name of the sub-process to be created. By default, a unique process name is assigned with the same base name as the parent process and a unique number.
7 /PROMPT
/PROMPT=string Specifies the prompt for DCL to use within the sub-process. By default, SPAWN copies the current prompt from the parent process.
8 /SYMBOLS
/SYMBOLS /NOSYMBOLS Specifies whether the system passes DCL global and local symbols to the sub-process. The default is /SYMBOLS.
9 /WAIT
/WAIT /NOWAIT Specifies whether the system waits until the current sub-process is completed before allowing more commands to be issued by the parent process. The default is /WAIT.
10 – Examples
CTF> SPAWN "SHOW SYSTEM" Spawns a sub-process in which a SHOW SYSTEM command is executed, after which control returns to the parent process. CTF> SPAWN /INPUT=CMDS.COM Spawns a sub-process and executes the DCL commands in CMDS.COM, after which control returns to the parent process. CTF> SPAWN /INPUT=CMDS.COM/OUTPUT=CMDS_OUT.LIS/NOWAIT Also executes the DCL commands in CMDS.COM, but returns control immediately to the parent process without waiting for the spawned sub-process to complete. Any output produced by the sub-process is written to CMDS_OUT.LIS.