Hide

What's this?

commandlinefu.com is the place to record those command-line gems that you return to again and again.

Delete that bloated snippets file you've been using and share your personal repository with the world. That way others can gain from your CLI wisdom and you from theirs too. All commands can be commented on, discussed and voted up or down.


Get involved!

You can sign-in using OpenID credentials, or register a traditional username and password.

First-time OpenID users will be automatically assigned a username which can be changed after signing in.

Universal configuration monitoring and system of record for IT.
Hide

Stay in the loop…

Follow the Tweets.

Every new command is wrapped in a tweet and posted to Twitter. Following the stream is a great way of staying abreast of the latest commands. For the more discerning, there are Twitter accounts for commands that get a minimum of 3 and 10 votes - that way only the great commands get tweeted.

» http://twitter.com/commandlinefu
» http://twitter.com/commandlinefu3
» http://twitter.com/commandlinefu10

Subscribe to the feeds.

Use your favourite RSS aggregator to stay in touch with the latest commands. There are feeds mirroring the 3 Twitter streams as well as for virtually every other subset (users, tags, functions,…):

Subscribe to the feed for:

Hide

News

May 19, 2015 - A Look At The New Commandlinefu
I've put together a short writeup on what kind of newness you can expect from the next iteration of clfu. Check it out here.
March 2, 2015 - New Management
I'm Jon, I'll be maintaining and improving clfu. Thanks to David for building such a great resource!
Hide

Top Tags

Hide

Functions

Psst. Open beta.

Wow, didn't really expect you to read this far down. The latest iteration of the site is in open beta. It's a gentle open beta-- not in prime-time just yet. It's being hosted over at UpGuard (link) and you are more than welcome to give it a shot. Couple things:

  • » The open beta is running a copy of the database that will not carry over to the final version. Don't post anything you don't mind losing.
  • » If you wish to use your user account, you will probably need to reset your password.
Your feedback is appreciated via the form on the beta page. Thanks! -Jon & CLFU Team

easily strace all your apache processes

Terminal - easily strace all your apache processes
ps auxw | grep sbin/apache | awk '{print"-p " $2}' | xargs strace
2011-03-14 21:45:22
User: px
Functions: awk grep ps xargs
7
easily strace all your apache processes

This one-liner will use strace to attach to all of the currently running apache processes output and piped from the initial "ps auxw" command into some awk.

Alternatives

There are 2 alternatives - vote for the best!

Terminal - Alternatives
ps h --ppid $(cat /var/run/apache2.pid) | awk '{print"-p " $1}' | xargs sudo strace
2012-03-21 01:59:41
Functions: awk cat ps sudo xargs
3

Like the original version except it does not include the parent apache process or the grep process and adds "sudo" so it can be run by user.

straceprocessname(){ x=( $(pgrep "$@") ); [[ ${x[@]} ]] || return 1; strace -vf ${x[@]/#/-p }; }
2009-12-03 00:04:39
User: sputnick
Functions: return strace
3

Especially for sysadmins when they don't want to waste time to add -p flag on the N processes of a processname.

In the old school, you did ;

pgrep processname

and typing strace -f -p 456 -p 678 -p 974...

You can add -f argument to the function. That way, the function will deal with pgrep to match the command-line.

Example :

processname -f jrockit
ps auxw | grep sbin/apache | awk '{print"-p " $2}' | xargs strace -f
2013-02-19 19:14:57
User: msealand
Functions: awk grep ps strace xargs
1

This version also attaches to new processes forked by the parent apache process. That way you can trace all current and *future* apache processes.

ps auxw | grep -E 'sbin/(apache|httpd)' | awk '{print"-p " $2}' | xargs strace -F
2016-08-04 10:59:58
User: gormux
Functions: awk grep ps strace xargs
Tags: awk grep ps strace
1

Will open strace on all apache process, on systems using sbin/apache (debian) or sbin/httpd (redhat), and will follow threads newly created.

ps -C apache o pid= | sed 's/^/-p /' | xargs strace

Know a better way?

If you can do better, submit your command here.

What others think

Why the inclusion of the the time of the running process only to use awk to separate out on the fs (:) to get the pid? On CentOS (tested on 5.5) this provides the same results:

ps auxw | grep sbin/httpd | awk '{print $2}' | awk ' {print "-p "$1}' | xargs strace
Comment by mrlinsky 299 weeks ago

Actually, this works as well on the same test env:

ps auxw | grep sbin/httpd | awk '{print"-p " $2}' | xargs strace
Comment by mrlinsky 299 weeks ago

Thanks @mrlinsky, I will update the command. I just put together a few bits and forgot to get rid of the extras while I tested it. :)

Comment by px 299 weeks ago

there, i shortened it for ya'll from 4 command pipe to 3.

strace $(pidof httpd | sed 's/\([0-9]*\)/\-p \1/g')
Comment by layer3switch 298 weeks and 6 days ago

@layer3switch, thank you kindly.

Comment by px 298 weeks and 6 days ago

Shorter: sh -c "strace -p{$(pgrep -d, apache)}"

Comment by akg240 298 weeks and 5 days ago

@akg240, that wouldn't work for fork() process as there is no way of knowing which calls are attached to which pid. the whole point of separate "-p" per pid is to associate calls per pid. also "sh -c" must include following string enclosed using single quote, not double quote.

Comment by layer3switch 298 weeks and 4 days ago

2016-1-26 xiaozhengm

http://www.coachfactory--outletonline.com

http://www.fitflopuk.me.uk

http://www.michaelkorsukbag.co.uk

http://www.get-coachoutletonline.org

http://www.michaelkors-handbag.me.uk

http://www.runningshoes.com.co

http://www.toms-outlet.cc

http://www.ugg-boots-store.com

http://www.louboutinshoes.cc

http://canadagoose.outletmalls.us.com

http://www.nike-blazerlow.fr

http://uggs.uggaustralia.qc.com

http://www.nikestoreuk.me.uk

http://www.true-religionjeans.net.co

http://coach.outletmalls.us.com

http://www.adidasshoes.name

http://michaelkors.adsmall.us.com

http://www.hermesbelt.in.net

http://www.mulberry-bags.org.uk

http://coach.eshopping.us.com

http://louisvuitton.outletmalls.us.com

http://www.hermesuk.org.uk

http://www.katespadeoutletsale.in.net

http://toms.adsmall.us.com

http://www.fitflopssaleclearance.com

http://michaelkors.eshopping.us.com

http://ugg.adsmall.us.com

http://www.louis-vuitton-outlet.us.com

http://www.canadagoosejackets.org.uk

http://ugg.eshopping.us.com

http://www.timberlanduk.me.uk

http://www.jordan13.org

http://christianlouboutin.outletmalls.us.com

http://www.coachoutlet-storeonline.in.net

http://www.instylermax.in.net

http://www.coachfactoryoutletus.in.net

http://www.coachoutlet-storeonline.us.com

http://tiffany.outletmalls.us.com

http://www.louboutin.org.uk

http://www.monclerjacketsoutlet.us.com

http://louboutin.adsmall.us.com

http://www.louisvuitton-borse.it

http://www.mcmhandbags.name

http://www.truereligion-outlet.com

http://www.new-balanceoutlet.us

http://www.louisvuitton-sac-pascher.fr

http://www.outlet-toms.cc

http://canadagoose.shopgioia.com

http://www.coach-factory-outlet-online.us.com

http://www.top-coachoutletstore.org

http://www.edhardy-outlet.name

http://www.jordan6.net

http://www.longchamphandbags.com.co

http://www.chaussurelouboutin-pascher.fr

http://www.ghdstraighteners.me.uk

http://www.nike-tn-pascher.fr

http://www.saclongchamp-solde.fr

http://www.coachcanadaoutlet.ca

http://burberryoutlet.outletmalls.us.com

http://sunglasses.outletmalls.us.com

http://www.michael--korsoutlet.us.com

http://www.nikefreeruns.uk

http://michaelkors.outletmalls.us.com

http://www.mk-michaelkorsoutletonline.com

http://www.cheaplouisvuittonhandbags.org

http://burberry.eshopping.us.com

http://www.michaelkors-outletonlines.in.net

http://www.airjordan-pascher.fr

http://www.ralphlaurenuk.me.uk

http://www.moncler-jackets.org

http://www.adidassuperstar.co.uk

http://abercrombie.shopgioia.com

http://www.authenticlouisvuittonhandbags.net

http://www.airforce1-nike.fr

http://www.coach-factoryoutlet.cc

http://www.coachoutletonlinespick.org

http://www.coachouletbtf.com

http://rayban.eshopping.us.com

http://www.ghdhairstraighteners.com.co

http://www.ralph-lauren-pas-cher.fr

http://ralphlauren.shopgioia.com

http://rayban.adsmall.us.com

http://www.mcmoutlet.us

http://www.louisvuittonuk.me.uk

http://www.jordan-femmepascher.fr

http://www.toms.in.net

http://burberry.outletmalls.us.com

http://www.cheap-uggsonsale.in.net

http://oakley.adsmall.us.com

http://www.basketballshoes.net.co

http://ugg.shopgioia.com

http://www.raybansoutlet.in.net

http://www.mizunorunningshoes.in.net

http://www.pandoracharms.com.co

http://www.truereligion-outlet.in.net

http://www.michaelkorsoutletoff.in.net

http://www.tomswedges.in.net

http://ugg.outletmalls.us.com

http://www.cheapjordansshoes.in.net

http://www.mymichaelkorssoutlets.org

http://www.airjordan-uk.org.uk

http://www.michaelkors-handbags.me.uk

http://www.nikeblazers.me.uk

http://burberry.shopgioia.com

http://timberland.adsmall.us.com

http://coach.adsmall.us.com

http://www.nike-airmax90.me.uk

http://www.nikesb.uk

http://www.nikerosherunwomen.me.uk

http://www.christianlouboutinuk.me.uk

http://www.ugg-boots-australia.com

http://www.adidas-trainers.me.uk

http://www.michaelkors-discount.com

http://www.polooutlet.us.com

http://www.niketrainers.com.co

http://www.airmax95.org.uk

http://www.montblancpens.us.org

http://www.adidasuk.org.uk

http://www.poloralphlauren.net.co

http://www.rolex-replicawatches.com.co

http://www.ralph-lauren.me.uk

http://www.jordan3.net

http://www.cheapwholesaleuggboots.com

http://hollister.shopgioia.com

http://www.michaelkorshandbags.cc

http://www.fitflops.in.net

http://www.snapbacks-wholesale.us

http://www.edhardyukclothing.me.uk

http://www.michaelkors-outlet-handbags.com

http://www.fitflops.us

http://www.raybans.org.uk

http://northface.outletmalls.us.com

http://nike.outletmalls.us.com

http://www.michaelkorsoutletforus.com

http://www.toryburchoutlet-sale.in.net

http://www.juicy-couture.us

http://www.raybansunglassesdeals.com.co

http://www.louis-vuittonhandbags.us

http://www.quality-outlet.com

http://christianlouboutin.eshopping.us.com

http://www.cheap-tomsoutlet.us

http://www.longchampoutlet.net.co

http://www.michaelkors-bags.me.uk

http://www.louisvuittonoutlets.name

http://www.coach-factoryoutlet.eu.com

http://www.tomsshoes.us.com

http://www.canadagooseoutlet.cc

http://canadagoose.adsmall.us.com

http://www.adidasgazelle.me.uk

http://christianlouboutin.shopgioia.com

http://www.kate-spadeoutlet.com.co

http://www.pradaoutlet.name

http://www.guccioutlet.com.so

http://www.jordan4.net

http://canadagoose.eshopping.us.com

http://www.michael-korshandbags.net.co

http://www.soccer-jerseys.us.com

http://www.nikerosheruns.me.uk

http://www.truereligion-outlet.net.co

http://oakley.shopgioia.com

http://www.sunglass-outlet.us

http://www.chiflatiron.in.net

http://www.tomsoutletstore.in.net

http://www.coachoutletstoreonlines.us

http://www.gucci-borse.it

http://www.jordan8.net

http://www.michaelkors-mkoutlet.in.net

http://www.chaussure-louboutin.fr

http://www.michaelkors-outletsale.com

http://www.michael-korsuk.me.uk

http://www.nike-airmax.org.uk

http://burberry.adsmall.us.com

http://www.montblanc-pens.name

http://www.sac-longchamppliage.fr

http://www.saclongchamp--pascher.fr

http://www.michaelkorsoutletvip.in.net

http://www.cheapjordans.com.co

http://www.louisvuitton-outletstores.org

http://www.marc-jacobs.in.net

http://www.pandorajewelryoutlet.name

http://www.christianlouboutinsell.net

http://www.michael-kors-handbags.uk

http://rayban.shopgioia.com

http://www.oakleysunglassesfake.in.net

http://www.kate-spadeoutlet.us

http://www.coach-factoryoutlet.com.co

http://www.gucci-outlet.org

http://www.adidas-shoes.me.uk

http://ralphlauren.eshopping.us.com

http://oakley.eshopping.us.com

http://www.vipmichaelkors-outletonline.com

http://www.canadagooseuk.me.uk

http://www.oakley--sunglasses.us.org

http://www.kate-spadeoutlet.in.net

http://truereligion.adsmall.us.com

http://jordan.outletmalls.us.com

http://www.guccioutlet.net.co

http://www.nikeuk.me.uk

http://www.katespadeuk.me.uk

http://www.christianlouboutinoff.us

http://www.nikecortez.com.co

http://www.nikehuarache.com.co

Comment by xiaozhengm 45 weeks ago

Your point of view

You must be signed in to comment.