Accessing System Information

CLIST REXX
LISTDSI statement 
LISTDSI &BASEDS
 LISTDSI external function 
x = LISTDSI(baseds)
&SYSOUTTRAP and &SYSOUTLINE 
SET SYSOUTTRAP = 100
 OUTTRAP external function 
x = OUTTRAP(var,100)
CONTROL statement 
CONTROL PROMPT
 PROMPT external function 
x = PROMPT(on)
&SYSDSN built-in function 
IF &SYSDSN('SYS1.MYLIB') = OK THEN
⋮
 SYSDSN external function 
IF SYSDSN('SYS1.MYLIB') = OK THEN
⋮
Control Variables:
For User Information 
&SYSPREF

  WRITE &SYSPREF

&SYSPROC
&SYSUID
For Terminal Information 
&SYSLTERM
&SYSWTERM
For CLIST Information 
&SYSENV
&SYSICMD
&SYSISPF
&SYSNEST
&SYSPCMD
&SYSSCMD
For System Information 
&SYSCPU
&SYSHSM
&SYSJES
&SYSLRACF
&SYSNODE
&SYSRACF
&SYSSRV
&SYSTERMID
&SYSTSOE
 Arguments of the SYSVAR external function:
For User Information 
SYSPREF

  SAY  SYSVAR(syspref)

SYSPROC
SYSUID
For Terminal Information 
SYSLTERM
SYSWTERM
For Exec Information 
SYSENV
SYSICMD
SYSISPF
SYSNEST
SYSPCMD
SYSSCMD
For System Information 
SYSCPU
SYSHSM
SYSJES
SYSLRACF
SYSNODE
SYSRACF
SYSSRV
SYSTERMID
SYSTSOE
Control Variables:
For System Information 
&SYSAPPCLU
&SYSDFP
&SYSMVS
&SYSNAME
&SYSSECLAB
&SYSSMFID
&SYSSMS
&SYSCLONE
&SYSPLEX
&SYSSYMDEF
 Arguments of the MVSVAR external function:
For System Information 
SYSAPPCLU
SYSDFP
SYSMVS
SYSNAME
SYSSECLAB
SYSSMFID
SYSSMS
SYSCLONE
SYSPLEX
SYMDEF