Tcl/Tk Documentation > TclCmd > pid
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.
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 $pipelineexec, open file, pipeline, process identifier
Copyright © 1995-1997 Roger E. Critchlow Jr. Copyright © 1993 The Regents of the University of California. Copyright © 1994-1996 Sun Microsystems, Inc.