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

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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(n), open(n)


KEYWORDS
       file, pipeline, process identifier

Tcl                                   7.0                               pid(n)