pid — Retrieve process identifiers
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.
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]
See also exec
Copyright © 1993 The Regents of the University of California.
Copyright © 1994-1996 Sun Microsystems, Inc.