pid(3tcl)

NAME

   pid - Retrieve process identifiers

SYNOPSIS

   pid ?fileId?
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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 identifier 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(3tcl), open(3tcl)

KEYWORDS

   file, pipeline, process identifier

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