'\" '\" Copyright (c) 1993 The Regents of the University of California. '\" Copyright (c) 1994-1996 Sun Microsystems, Inc. '\" '\" See the file "license.terms" for information on usage and redistribution '\" of this file, and for a DISCLAIMER OF ALL WARRANTIES. '\" '\" RCS: @(#) $Id: pid.n,v 1.1.1.1 2007/07/10 15:04:23 duncan Exp $ '\" .so man.macros .TH pid n 7.0 Tcl "Tcl Built-In Commands" .BS '\" Note: do not modify the .SH NAME line immediately below! .SH NAME pid \- Retrieve process identifiers .SH SYNOPSIS \fBpid \fR?\fIfileId\fR? .BE .SH DESCRIPTION .PP If the \fIfileId\fR argument is given then it should normally refer to a process pipeline created with the \fBopen\fR command. In this case the \fBpid\fR 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 \fIfileId\fR refers to an open file that isn't a process pipeline. If no \fIfileId\fR argument is given then \fBpid\fR returns the process identifier of the current process. All process identifiers are returned as decimal strings. .SH EXAMPLE Print process information about the processes in a pipeline using the SysV \fBps\fR program before reading the output of that pipeline: .PP .CS set pipeline [open "| zcat somefile.gz | grep foobar | sort -u"] # Print process information exec ps -fp [\fBpid\fR $pipeline] >@stdout # Print a separator and then the output of the pipeline puts [string repeat - 70] puts [read $pipeline] close $pipeline .CE .SH "SEE ALSO" exec(n), open(n) .SH KEYWORDS file, pipeline, process identifier