Concerning request for help on shell background processes

Phil Pfeiffer pfeiffer at rsch.WISC.EDU
Wed Sep 17 07:17:12 AEST 1986


Sorry, I mistyped an important character in the original request.
Let's try again.

+ 
+ The systems in question are 4.3BSD Unix and Ultrix.
+ The problem is as follows:
+ 
+ 
+ Assume that file "nxf" does not exist.
+ Assume that the following lines are in shell script 'cmd':
+  
+   #!/bin/csh
+   rm nxf         >& cmd_out
+   echo $status   >  cmd_stat
+ 
+ 
+ Assume the following lines are in shell script 'master': 
+ 
+  #!( doesn't matter whether master is executed using "/bin/sh" or "/bin/csh" )
+   cmd
+ 
+ 'master', as is, executes just fine.  The "cannot find file" error message and
+ error status values are written into cmd_out and cmd_stat, respectively.
+ 
       Let me clarify this:    the "cmd_stat" file contains a "1".
	   so far, all well and good.

+ 
+ Assume the following lines are in shell script 'bgmaster': 
+ 
+  #!( doesn't matter whether master is executed using "/bin/sh" or "/bin/csh" )
+   cmd &
+   wait
+ 
+ Now "cmd_out" is empty on return, and "cmd_stat=1".   Why?
                                         ^^^^^^^^^^
This phrase in the original message should have asserted that "cmd_stat=0".

Have I failed to understand something about /bin/csh background processing?


-- 
-- Phil Pfeiffer

...!{harvard,ihnp4,seismo,topaz}!uwvax!pfeiffer
(608) 263-7308



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