hi
A quick question:
Is there an easy way to check if a process is running given it's PID? There
seems to be nothing like Process.exists?(pid). If I was root I could use
Process.kill(0,pid) to test, but the program needs to run as a plain user. Do
I have to parse the output from ps -e?
Thanks in advance 
--
George Mochrie
aka Drasil
ICQ# 84423409
George Mochrie wrote:
hi
A quick question:
Is there an easy way to check if a process is running given it's PID? There seems to be nothing like Process.exists?(pid). If I was root I could use Process.kill(0,pid) to test, but the program needs to run as a plain user. Do
Not only root can do kill(0, pid), any user can send signal (or 0) to his/her own processes.
On systems that have /proc you can also check for presence of a directory named like pid there.
I have to parse the output from ps -e?
Thanks in advance
Gennady.
def alive? pid
#{{{
pid = Integer("#{ pid }")
begin
Process.kill 0, pid
true
rescue Errno::ESRCH
false
end
#}}}
end
the module
require 'pathname'
require 'socket'
module Util
#{{{
class << self
def export sym
#{{{
sym = "#{ sym }".intern
module_function sym
public sym #}}}
end
def append_features c
#{{{
super
c.extend Util #}}}
end
end
def mcp obj
#{{{
Marshal.load(Marshal.dump(obj))
#}}}
end
export 'mcp'
def klass
#{{{
self.class
#}}}
end
export 'klass'
def realpath path
#{{{
path = File.expand_path "#{ path }"
begin
Pathname.new(path).realpath.to_s
rescue Errno::ENOENT, Errno::ENOTDIR
path
end
#}}}
end
export 'realpath'
def hashify(*hashes)
#{{{
hashes.inject(accum={}){|accum,hash| accum.update hash}
#}}}
end
export 'hashify'
def getopt opt, hash
#{{{
opt_s = "#{ opt }"
hash[opt] || hash[opt_s] || hash[opt_s.intern] #}}}
end
export 'getopt'
def alive? pid
#{{{
pid = Integer("#{ pid }")
begin
Process.kill 0, pid
true
rescue Errno::ESRCH
false
end
#}}}
end
export 'alive?'
def maim(pid, opts = {})
#{{{
sigs = getopt('signals', opts) || %w(SIGTERM SIGQUIT SIGKILL)
suspend = getopt('suspend', opts) || 4
pid = Integer("#{ pid }")
sigs.each do |sig|
begin
Process.kill(sig, pid)
rescue Errno::ESRCH
return nil
end
sleep 0.2
unless alive?(pid)
break
else
sleep suspend
end
end
not alive?(pid)
#}}}
end
export 'maim'
def timestamp time = Time.now
#{{{
usec = "#{ time.usec }"
usec << ('0' * (6 - usec.size)) if usec.size < 6
time.strftime('%Y-%m-%d %H:%M:%S.') << usec
#}}}
end
export 'timestamp'
def stamptime string, local = true #{{{
string = "#{ string }"
pat = %r/^\s*(\d\d\d\d)-(\d\d)-(\d\d) (\d\d):(\d\d):(\d\d).(\d\d\d\d\d\d)\s*$/o
match = pat.match string
raise ArgumentError, "<#{ string.inspect }>" unless match
yyyy,mm,dd,h,m,s,u = match.to_a[1..-1].map{|m| m.to_i}
if local
Time.local yyyy,mm,dd,h,m,s,u
else
Time.gm yyyy,mm,dd,h,m,s,u
end
#}}}
end
export 'stamptime'
def escape! s, char, esc
#{{{
re = %r/([#{0x5c.chr << esc}]*)#{char}/
s.gsub!(re) do
(($1.size % 2 == 0) ? ($1 << esc) : $1) + char
end
#}}}
end
export 'escape!'
def escape s, char, esc
#{{{
ss = "#{ s }"
escape! ss, char, esc
ss
#}}}
end
export 'escape'
def fork(*args, &block)
#{{{
begin
verbose = $VERBOSE
$VERBOSE = nil
Process.fork(*args, &block)
ensure
$VERBOSE = verbose
end
#}}}
end
export 'fork'
def exec(*args, &block)
#{{{
begin
verbose = $VERBOSE
$VERBOSE = nil
Kernel.exec(*args, &block)
ensure
$VERBOSE = verbose
end
#}}}
end
export 'exec'
def hostname
#{{{
@__hostname__ ||= Socket::gethostname
#}}}
end
export 'hostname'
def host
#{{{
@__host__ ||= Socket::gethostname.gsub(%r/\..*$/o,'')
#}}}
end
export 'host'
def emsg e
#{{{
"<#{ e.class }> - <#{ e.message }>"
#}}}
end
export 'emsg'
def btrace e
#{{{
(e.backtrace or ).join("\n")
#}}}
end
export 'btrace'
def errmsg e
#{{{
emsg(e) << "\n" << btrace(e)
#}}}
end
export 'errmsg'
def erreq a, b
#{{{
a.class == b.class and
a.message == b.message and
a.backtrace == b.backtrace
#}}}
end
export 'erreq'
#}}}
end # class Util
regards
-a
On Thu, 26 Aug 2004, George Mochrie wrote:
hi
A quick question:
Is there an easy way to check if a process is running given it's PID? There
seems to be nothing like Process.exists?(pid). If I was root I could use
Process.kill(0,pid) to test, but the program needs to run as a plain user. Do
I have to parse the output from ps -e?Thanks in advance
--
George Mochrie
aka Drasil
ICQ# 84423409
from my util module:
EMAIL :: Ara [dot] T [dot] Howard [at] noaa [dot] gov
PHONE :: 303.497.6469
A flower falls, even though we love it;
and a weed grows, even though we do not love it. --Dogen
===============================================================================
many thanks, /proc will do fine 
On Wednesday 25 August 2004 22:01, Gennady wrote:
George Mochrie wrote:
> hi
>
> A quick question:
>
> Is there an easy way to check if a process is running given it's PID?
> There seems to be nothing like Process.exists?(pid). If I was root I
> could use Process.kill(0,pid) to test, but the program needs to run as a
> plain user. DoNot only root can do kill(0, pid), any user can send signal (or 0) to
his/her own processes.On systems that have /proc you can also check for presence of a
directory named like pid there.> I have to parse the output from ps -e?
>
> Thanks in advanceGennady.
--
George Mochrie
aka Drasil
ICQ# 84423409
George Mochrie wrote:
hi
A quick question:
Is there an easy way to check if a process is running given it's PID? There seems to be nothing like Process.exists?(pid). If I was root I could use Process.kill(0,pid) to test, but the program needs to run as a plain user. DoNot only root can do kill(0, pid), any user can send signal (or 0) to his/her own processes.
On systems that have /proc you can also check for presence of a directory named like pid there.
You can't send a signal, but you get a different error:
mark@eMac% irb --prompt xmp
Process.kill 0, 1
Errno::EPERM: Operation not permitted
from (irb):2:in `kill'
from (irb):2
Process.kill 0, 512
Errno::ESRCH: No such process
from (irb):3:in `kill'
from (irb):3
Process.kill 0, 419
==>1
process 1 is owned by root, 512 doesn't exist, 419 was mine.
So, Process.exists? could be:
def Process.exists?(pid)
Process.kill 0, pid
return true
rescue Errno::ESRCH
return false
rescue Exception
return true
end
==>nil
Process.exists? 1
==>true
Process.exists? 512
==>false
Process.exists? 419
==>true
On Aug 25, 2004, at 2:01 PM, Gennady wrote:
I have to parse the output from ps -e?
Thanks in advanceGennady.
the perfect solution... thanks
On Wednesday 25 August 2004 22:26, Mark Hubbart wrote:
On Aug 25, 2004, at 2:01 PM, Gennady wrote:
> George Mochrie wrote:
>> hi
>> A quick question:
>> Is there an easy way to check if a process is running given it's PID?
>> There seems to be nothing like Process.exists?(pid). If I was root I
>> could use Process.kill(0,pid) to test, but the program needs to run
>> as a plain user. Do
>
> Not only root can do kill(0, pid), any user can send signal (or 0) to
> his/her own processes.
>
> On systems that have /proc you can also check for presence of a
> directory named like pid there.You can't send a signal, but you get a different error:
mark@eMac% irb --prompt xmp
Process.kill 0, 1
Errno::EPERM: Operation not permitted
from (irb):2:in `kill'
from (irb):2Process.kill 0, 512
Errno::ESRCH: No such process
from (irb):3:in `kill'
from (irb):3Process.kill 0, 419
==>1process 1 is owned by root, 512 doesn't exist, 419 was mine.
So, Process.exists? could be:
def Process.exists?(pid)
Process.kill 0, pid
return true
rescue Errno::ESRCH
return false
rescue Exception
return true
end
==>nilProcess.exists? 1
==>trueProcess.exists? 512
==>falseProcess.exists? 419
==>true>> I have to parse the output from ps -e?
>> Thanks in advance
>
> Gennady.
--
George Mochrie
aka Drasil
ICQ# 84423409