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Full Discussion: Pipelining
Top Forums Shell Programming and Scripting Pipelining Post 78253 by muthukumar on Monday 18th of July 2005 07:35:34 AM
Old 07-18-2005
You have taken correct way. $? will give status of prev command. we can not make it with single utility to give return code and redirect output to another log file. You can do it better as,

# proc > logfile
RC=$?
tee -a <logfile> < logfile
print "$RC"

where, < <filename> is faster than cat <filename>

That is all.
 

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pid(n)                                                         Tcl Built-In Commands                                                        pid(n)

__________________________________________________________________________________________________________________________________________________

NAME
pid - Retrieve process identifiers SYNOPSIS
pid ?fileId? _________________________________________________________________ DESCRIPTION
If the fileId argument is given then it should normally refer to a process pipeline created with the open command. In this case the pid command will return a list whose elements are the process identifiers of all the processes in the pipeline, in order. The list will be empty if fileId refers to an open file that is not a process pipeline. If no fileId argument is given then pid returns the process identi- fier of the current process. All process identifiers are returned as decimal strings. EXAMPLE
Print process information about the processes in a pipeline using the SysV ps program before reading the output of that pipeline: set pipeline [open "| zcat somefile.gz | grep foobar | sort -u"] # Print process information exec ps -fp [pid $pipeline] >@stdout # Print a separator and then the output of the pipeline puts [string repeat - 70] puts [read $pipeline] close $pipeline SEE ALSO
exec(n), open(n) KEYWORDS
file, pipeline, process identifier Tcl 7.0 pid(n)
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