REXX tool for replacing a particular string in all the members of a PDS

CAWABATC tool can be used for replacing a particular string in all the members of a PDS provided CAFM is available in your shop.  However this does not work fine when the target string is longer than source string and the tool overwrites spaces next to the string to be replaced with the new string.

Below REXX tool works perfectly fine for replacing a particular string in all the members of a PDS. Save the REXX code with member name 'STRREPL' in a PDS and you can use below mentioned JCL to run the REXX code in batch. Use your own PDS name in SYSEXEC file.

REXX code :

/* REXX */                
PARSE UPPER PULL DSN      
PARSE UPPER PULL SRCSTR   
PARSE UPPER PULL TRGSTR  
SRCSTR = SPACE(SRCSTR)   
TRGSTR = SPACE(TRGSTR)      
DUMMY = OUTTRAP("MEMB.","*")
ADDRESS TSO                  
"LISTDS '"DSN"' MEMBERS" 
DUMMY = OUTTRAP("OFF")    
DO I = 7 TO MEMB.0         
     DSN1 = "'"||DSN||"("||SPACE(MEMB.I,0)||")'" 
     DROP OUT.        
     ADDRESS TSO                       
     "ALLOC F(IN) DS("DSN1") SHR"   
     "EXECIO * DISKR IN (FINIS STEM IN." 
     "FREE F(IN)"     
      T = 0                     
      DO S = 1 TO IN.0
        STRING = IN.S 
        CALL STRRPL
        T = T + 1 
        OUT.T = STRING
      END     
      OUT.0 = IN.0  
      ADDRESS TSO          
      "ALLOC F(OUT) DS("DSN1") SHR" 
      "EXECIO * DISKW OUT (FINIS STEM OUT."
      "FREE F(OUT)"  
END       
EXIT          
STRRPL:         
DO FOREVER     
POSN = POS(SRCSTR,STRING)               
 IF POSN > 0                            
 THEN DO                                
  SUBLEN= LENGTH(SRCSTR)                
  STRLEN= LENGTH(STRING)                
  FPART = SUBSTR(STRING,1,POSN-1)       
  SPART = SUBSTR(STRING,POSN+SUBLEN)    
  STRING= FPART||TRGSTR||SPART ; END    
 ELSE DO                                
  LEAVE ;END                            
END                                     
RETURN  

                              

JCL step to excute the tool in batch :

//STEP1   EXEC PGM=IKJEFT01,PARM='STRREPL'         
//*                                                
//SYSTSIN  DD   *                                  
N123DF.G6279.COMMON.TEST                           
S6578                                              
S68779                                             
/*                                                 
//SYSTSPRT DD   SYSOUT=*                           
//*                                                
//SYSEXEC  DD   DSN=N123DF.REXX.CODE,DISP=SHR     
//* N123DF.REXX.CODE CONTAINS MEMBER STRREPL