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Comment by thaumaturgy | Hacker News Reader

Serious question: what would be a better way to do this?

As per other users, you can use pkill but it's not entirely portable in meaning between OSs. This software had to run on just about every possible Unix out there. Solaris, HP-UX, AIX, many others ...

My main point is that using perl and grep, (multiple thereof!) is nuts when you can do it all in perl.

Also crazy was using -ef (all processes) when the process of interest was using a known user. So ps -u <user> would be more appropriate.

Doing as much in Perl as possible, for portability, you'd do something like

  ps -u <user>| perl -ane 'm/[S]omeDaemon/ && kill "SIGTERM", $F[1]'

-a means autosplit into fields, $F[0], F[1], etc so the pid is $F[1].

See `perldoc -f kill` for the Perl function kill.

You can also do the `ps` from within Perl but I don't think you'd be gaining much in readability or portability.

If it's something you need to do on a semi-regular basis, using a pidfile seems to me to be the best solution. Instead of trying to be clever about pipelines, just write the pid(s) to a file and use that.

That's the right way to do it but you always need a backup method to use in case the process dies without removing the pidfile.

Or use a dedicated uid for the daemon. You probably want that anyway.

I would just recommend pkill: https://en.wikipedia.org/wiki/Pkill

I tend to use the following command:

    kill -HUP $(pidof SomeDaemon)

and if it insists on running, I use:

    sudo kill -9 $(pidof SomeDaemon)

That's it, really.

I suggest:

    killall -HUP SomeDaemon

Don't do this! Not only is pkill more competent, it is available on several other operating systems.

There is a killall on Solaris also which is very different but true to its name. You do not want to run it by accident.

pgrep is also useful if you're not trying to kill. They're both from Solaris, and if you have one, you have the other. pgrep | xargs can also be very useful on occasion, depending on what you're doing (mainly debugging).

> xargs can also be very useful on occasion

yes, and xargs has a particularly useful argument -P that allows to do stuff in parallel and probably deserves more love :P

Top tip!

`pkill -v` is not verbose mode!

Remember pkill is next to pgrep...

I often roll with 'pgrep' part of pkill package to fetch the pids of either the ucomm or longname (-l) of the process.

pgrep -l 'reg.*ex" | xargs -L1 do-stuff

or just pkill if the idea is just to send a signal.

To gather particular process metrics, ps can be invoked with process ids (-p), with full control of its output (-o), grep is rarely needed.

perl -e 'print `pgrep SomeDaemon `'

  do_something_with_pids $(ps -C SomeDaemon ho pid)

Though it's GNU procps.

PowerShell?

In a script:

Get-Process | Where-Object { $_.ProcessName -eq 'SomeDaemon' } | Stop-Process

Or at the command line:

ps | ? { $_.ProcessName -eq 'SomeDaemon' } | kill

A pid file is the best IMO

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