Ask Ubuntu General Room

Serg

8:01 AM

yeah, probably that's the easiest solution. There should also be some form of logging utils

Edity

:D

Byte Commander

@Serg And how do I calculate how old a timestamp is in seconds?

Edity

I didn't know Paper Mario could be this fun

Serg

Who edited my post ?

I was working on it

Edity

not me

Serg

8:06 AM

oh, terdon

Edity

im playing paper mario

Serg

it's ok, i'll just add stuff

terdon

@Serg Looks good.

@Serg Ah, sorry, I just fixed the backticks, they were breaking your formatting.

edwinksl

^itchy fingers

Serg

@terdon cool, thanks ^_^ I added a bit more stuff to the answer. Didn't even notice that those backticks were breaking the answer

terdon

8:13 AM

@Serg xargs is POSIX, not GNU, you don't need the disclaimer.

Serg

oh, ok . . .will fix that in a jiffy

So ... today i learned how to use my power bank thingy . . . which i bought for my trip in China . . . and left it home, because i didn't know how to use it then. . .

And they didn't have instructions

So I couldn't RTFM

edwinksl

rare occasion where RTFM is not applicable

Serg

yeah, it's hard to RTFM without TFM . . . although I should have googled . . . I also should have guessed that the powerbank doesn't have any initial charge

Zanna

for many things I find I cannot make sense of TFM when I attempt to R it. Maybe it's a certain specialness of me

Serg

depends on the language TFM is written in. If it's too technical , then yeah, it won't make sense. Also lack of examples . . . .I hate man pages without examples

Zanna

8:26 AM

I really need examples

and diagrams

and to try it out for myself... I understand & learn by doing

Serg

yeah . . . same here

Zanna

and for most people I think the same is true. but the writers of TFMs seem rarely to be aware of this

Serg

They're aware. Some just don't like doing documentation. Writing print_usage() function in my scripts is a bother , because i know what the script does. I just know that other users will need it

2:32 AM . . .

CodeX

Good morning

Serg

Good evening here . . . . or rather night

CodeX

8:33 AM

hmm 11:30 here .. and I just woke up

Zanna

@Serg aaah true. Personally I love to Explain Things :)

Byte Commander

@Serg Can you please look over my little script here, it seems not to work: gist.github.com/ByteCommander/5ecf6a989e25159eb1283988e3d2b5d5

It refoxes firestart when the power button is pressed once, but does not detect double presses to shut down the machine.

(advice by anybody else who knows Bash is also appreciated of course)

Edity

omg so much time

Byte Commander

I found the problem, but don't understand why:

When I manually sudo touch /tmp/powerbtn-touched and run the script immediately afterwards, it wants to reboot.

But the script does not correctly touch that file itself to update the timestamps.

Why???

Serg

@ByteCommander is the temp file created before script starts running ?

Byte Commander

8:48 AM

No.

It may be created, but not necessarily.

Therefore I added the -e check.

The problem seems to be the touch command that does not modify the timestamp propoerly.

for whatever reason.

Serg

@ByteCommander what exactly you're trying to do and is that from a question ?

CodeX

2

Byte Commander

@Serg It is for a question, but not directly asked that way. I want to use the power button to run a custom script when pressed once (and do not shut down) and to shut down the normal way when it is pressed twice within 5 seconds.

It works if I do not check the timestamp and touch the file but echo the current time into the file and check its content.

Why the heck is simple touch broken that way?

CodeX

touch works for me if manually done

Byte Commander

manually it works for me too, but not in the script!

@Serg I updated the Gist, this time it works.

CodeX

8:59 AM

damn it restarted my firefox .. BRB

Byte Commander

that's what it is supposed to do...

But although it now prints "rebooting" when running manually twice within 5s, it does not reboot although I uncommented that line.

CodeX

it does update the time for me ..even using your script

Serg

@ByteCommander so i played around with the old version. Aside from doing "if [ -e "$mytempfile" ]" I didn't change anything else (except commenting out killing firefox). File gets touched ok within 5 seconds

Byte Commander

o.O?

Serg

I mean , if I wait more than 5 seconds , it shows me else part, if less than 5 seconds - it's if part

Byte Commander

9:05 AM

But why...

Serg

@ByteCommander does it work if you add -m optin to touch ?

touch -m "$mytempfile"

Byte Commander

Yup, seems like the -m fixes it.

But why does touch behave differently in a script than manually?

Serg

No idea. There's no subshell, so we can't blame that

3

Q: terminal command | grep IP

ifconfig -a | grep 10.16 inet 10.16.x.xx netmask 0xffffff00 broadcast 10.16.x.xxx inet 10.16.x.xx netmask 0xffffff80 broadcast 10.16.x.xxx I have replaced the numbers with x My aim is to remove everything apart from the inet IP's. so it just shows as: 10.16.x.xx 10.16.x.xx Is thi...

^ This guy apparently uses Mac OS X

question is relevant to ubuntu though

terdon

@Serg why in the world did you vote to close this?

Serg

@terdon Kali

edwinksl

9:16 AM

guess not anymore

terdon

@Serg Oh, good grief, I didn't even notice that. Makes no difference whatsoever though, so I just removed mention of Kali.

Serg

Sure , that works.

edwinksl

spam askubuntu.com/a/798482/15003

Serg

@terdon do we keep this one as well with tags and comments removed ? askubuntu.com/q/797452/295286

Mec OS Z

How the heck it just became 3:21 AM ????

terdon

@Serg That one's trickier. The output format of ifconfig is different on the mac (matched what I get on my Arch, apparently, which is why I didn't even realize they were using a mac). That made the first version of my solution break on Ubuntu.

Yeah, OK, I migrated that one away.

SmokeDetector

9:23 AM

[ SmokeDetector ] Manually reported answer: How to write comment in .vimrc file? by user568221 on askubuntu.com …

Serg

Need to ask someone if Macs have ip command

Byte Commander

Good grief!

My script restarts Firefox, but as ROOT! O.O

Serg

baaaad idea

edwinksl

kittens died because of that

Byte Commander

I guess a few kittens just died...

Serg

9:25 AM

@edwinksl @ByteCommander are you two related ?

edwinksl

lmao

Byte Commander

>.>

edwinksl

great minds think of kittens

Byte Commander

So... how can a command running as root restart a user's firefox process as this user?

Serg

em . . . su ?

Byte Commander

9:27 AM

Does su require target user password if running as root?

terdon

@ByteCommander No, but why su? Use sudo -u $user command

Byte Commander

Yeah.

And how do I find out which users' Firefox I just murdered?

Or I just hard-code the user...

well, no. Once I typed it, it sounds like a bad idea.

But it would be easy as killall also has an -u option.

Serg

@ByteCommander

$ pgrep -u 1000 firefox
12284

Then use kill $PID

or just pkill

Byte Commander

Or killall -u 1000 firefox.

Serg

or that

Byte Commander

9:30 AM

Btw, how do I kill softly?

Serg

With a soft pillow ?

Byte Commander

I thought SIGTERM would be soft, but it crashes Firefox.

Serg

yeah, that's what it does. Soft kills are handled by X server

you need wmctrl for soft kills

like if you kill gnome-terminal it won't ask for confirmtion, but if you use wmctrl it will

because signals for that come from X server

and wmctrl does exactly that

it doesn't send sigterm

terdon

@ByteCommander try SIGQUIT or SIGINT

Serg

doesn't work either @terdon I have played with that many times

Byte Commander

9:33 AM

SIGQUIT also brings up the restore last session dialogue.

Jacob Vlijm

What @Serg sais ^

Serg

Reading wmctrl source code was quite beneficial , by the way

Byte Commander

And how do I find out the Firefox window?

terdon

@Serg How does it softkill then?

Byte Commander

wmctrl -c Firefox works. Thanks!

Jacob Vlijm

9:37 AM

$(wmctrl -l | grep 'Mozilla Firefox' | tail -1 | awk '{ print $1 }')

@ByteCommander your command is not reliable

Byte Commander

So I will first try to soft-kill Firefox, wait 5 seconds and then hard-kill it.

terdon

$(wmctrl -l | awk '/Mozilla Firefox/{k=$1}END{print k}')

Jacob Vlijm

...it closes the first found window with Firefox in it

Byte Commander

right...

Jacob Vlijm

@terdon not the best

Byte Commander

9:38 AM

But yours closes the first window with "Mozilla Firefox" in it.

Jacob Vlijm

better by window id

terdon

@JacobVlijm Why? It's just the same as yours, only more efficient.

Serg

@terdon source code has this function : static int close_window (Display *disp, Window win); That function ( in main.c )

That function is basically this

Jacob Vlijm

ooops, copied the wrong one...

Serg

static int close_window (Display *disp, Window win) {/*{{{*/
    return client_msg(disp, win, "_NET_CLOSE_WINDOW",
            0, 0, 0, 0, 0);
}/*}}}*/

it sends _NET_CLOSE_WINDOW to X server

Jacob Vlijm

9:39 AM

$(wmctrl -lp | grep "$(pgrep firefox)" | tail -1 | awk '{ print $1 }')

wmctrl -ic "$(wmctrl -lp | grep "$(pgrep firefox)" | tail -1 | awk '{ print $1 }')"

terdon

@Serg And what does that do, I wonder?

Jacob Vlijm

....to be complete @terdon, @ByteCommander

@terdon it closes the window gracefully

really gracefully

6

A: How do I close a new Firefox window from the Terminal?

To make a command that finds the id of the last window, created by Firefox (and to close it), you will need wmctrl to be installed: sudo apt-get install wmctrl The command Then use the command: wmctrl -ic "$(wmctrl -l | grep 'Mozilla Firefox' | tail -1 | awk '{ print $1 }')" Explanation:...

terdon

I guess, I'm just wondering how. SIGHUP is the soft kill, but firefox must not be dealing with it correctly.

Jacob Vlijm

The last version closes by pid ^

Serg

@terdon gui apps respond to X server messages and trap those . Unless it's hard coded, they don't trap SIGHUP or SIGKILL

By the way, the post Jacob has linked was the one which prompted me to read source code of wmctrl and what it does

Actually , no

not that one

Byte Commander

9:44 AM

SIGKILL can not be caught.

Serg

askubuntu.com/q/753033/295286 This one

Awww, but i wanted to downvote that post ！

deleted too soon

Byte Commander

@JacobVlijm How does this behave when running as root?

Will it kill all users' Firefoxes?

How can I limit that to one single user?

The simplest thing would be sudo -u <UID> wmctrl...

right?

Stefano Palazzo

@NathanOsman docker is like a cardboard cutout of virtualisation

(:

Jacob Vlijm

@ByteCommander the first thought that comes into mind is that sudo wmctrl -lp only lists windows of the current user's x-session

Byte Commander

But if the script runs as true root and not with sudo?

Jacob Vlijm

9:54 AM

do you ever run firefox as root btw?

terdon

@ByteCommander Why would there be a difference? All that changes are a couple of environmental variables.

Byte Commander

That's the point.

Does wmctrl always only operate on the current active user?

I'll just sudo -u into the target user, that should be safe.

James

@NathanOsman @serg yup!

@serg learnrubythehardway.org/book

Byte Commander

@JacobVlijm Btw, wmctrl does not block if the window does not react and stays open, right? The script will continue immediately without waiting?

James

Start with that. HTML version is free.

Serg

9:58 AM

@James Nathan was referring Androind guy to you , i think , but I am still glad to see you :) Also I know of that book , actually wanted to buy it

Jacob Vlijm

@ByteCommander subprocess.call() waits for it to finish

Serg

@ByteCommander i'm gonna ponder this thingy of yours. Interesting idea . . . might even write something that doesn't require root

Jacob Vlijm

Subprocess.Popen() does not...

Byte Commander

I'm in a Bash script, not Python.

Serg

time to port bash script to python maybe ?

Byte Commander

10:00 AM

I want to send the soft quit signal to all windows, wait 5 seconds and then hard-kill the remaining ones.

Jacob Vlijm

In python, a piece of cake

...using thread

Byte Commander

But I'm in Bash.... :P

Jacob Vlijm

Poor guy :)

Byte Commander

Do I have to send it to background then?

Jacob Vlijm

FINALLY justice :)

Byte Commander

10:01 AM

sudo -u USER wmctrl ... &

Jacob Vlijm

I don't know the most efficient way in bash...

Serg

@James and speaking of PHP . . . is it worth learning it nowadays ?

Jacob Vlijm

Oh yes ^

Byte Commander

just has to work... efficiency is not important here

Jacob Vlijm

The thing is that you need to time the 5 seconds while the closing is being tried, you need something like a second thread as far as I can see

Byte Commander

10:04 AM

wmctrl returns immediately. Just tested.

So I simply do wmctrl, sleep 5, killall.

Jacob Vlijm

...not of you get the dialogue

Byte Commander

Yes it does.

Tried with a gedit window.

Serg

@ByteCommander what should your action be for double press ? shutdown ?

Byte Commander

it asked me whether I want to save and stayed open, but wmctrl returned anyway.

@Serg yes.

Serg

@ByteCommander well use dbus . . . that doesn't need root, and you can run your whole scripto as regular user

Jacob Vlijm

10:06 AM

@ByteCommander you are right, just tried!

Serg

hold on

James

@Serg yes! PHP is finally fixing many of the issues that got it a bad name.

The world needs more good PHP devs.

Byte Commander

@Serg No I can't - it will get called by the acpi daemon which runs as root.

Jacob Vlijm

@ByteCommander then the script runs on, in python as well.

Serg

@ByteCommander use qdbus com.canonical.Unity /com/canonical/Unity/Session com.canonical.Unity.Session.Shutdown

To shutdown

And use this :

netcat -U /var/run/acpid.socket

For reading power button press

Byte Commander

10:08 AM

@Serg what's the benefit over shutdown now?

Serg

benefit is that you don't need root

And since it's a Unity dbus call, it should work better I think ?

Byte Commander

But then I have to manually poll this socket instead of waiting to get called...

Serg

Yes . . . what's wrong with polling ?

Byte Commander

How would I do that?

Serg

netcat -U /var/run/acpid.socket | while read LINE ; do . . . done

Then you can use grep for "LNXPWRBN"

Byte Commander

10:11 AM

Sounds reasonable.

Then I also would not have to mess around with the acpi scripts.

Thanks! :)

Serg

And you can save time stamp ( date +%s ) to a variable. If old time stamp is less than new timestamp , then do A. Else , do B and save old timestamp

You're very very welcome ^_^

Byte Commander

I guess I'll start a proper github repo for this now.

2

A gist seems not enough.

Really? Why is that star-worthy... >.<

Serg

@ByteCommander you should have started the repo long time ago :p This script still can be as a gist, unless you plan to have multiple scriptos interacting

Also, not my star . . .but have another one

Byte Commander

xD

Serg

@ByteCommander do you want me to provide you an example of polling ( for inspiration ) ?

Byte Commander

10:16 AM

Any cool name proposals for the repo?

Serg

SergIsAwesome

How's that ?

Byte Commander

No thanks, I think the netcat | while read thing above is enough.

Nope.

UniversalPowerButton maybe?

But that's a bit long...

Serg

neopb

neo-power-button

Byte Commander

hmm... :/

Serg

@ByteCommander just make a general repo for all AskUbuntu scripts

that's what i do

i post most serious scripts to sergrep repo

Byte Commander

10:21 AM

I made an org for Ask Ubuntu answer scripts once...

But it still only contains 2 repos...

Serg

so add another one. AskUbuntuGeneralScripts

and since i mentioned sergrep , here it is github.com/SergKolo/sergrep

awful name, but at least people know it's mine

Byte Commander

Why should I add a general repo?

Serg

well, why add a repo for just one script ?

Byte Commander

Why not?

Serg

sure, can be done. repos typically are for multiple files though

Byte Commander

10:35 AM

I have at least a readme and a license file.

But this one will contain more files anyway.

Serg

@ByteCommander so what do yoi wanna do with this script ? do you wanna add action for more keypresses ?

Byte Commander

Maybe. I especially think of custom actions scripts

Serg

nice, nice !

I would love to contribute to this project at some point

@ParanoidPanda Wagakki have new music video out :D youtu.be/UyuzfQkUlyY

Zacharee1

wow, the Axon 7 is only $400

Serg

@Zacharee1 how are you up this early ?

Zacharee1

10:48 AM

dunno

why are you?

Serg

because i am a night owl who cant control my sleep even if i tried

and i tried many times

ok, im out. 88

Byte Commander

@Serg FSCK you, GEMA. :-/

not in the mood for youtube over tor browser at the moment...

Uh... I think I have to use Python anyway...

Serg

yay for censorship . . . .@ByteCommander use tiger proxy maybe ? i use that site sometimes

@ByteCommander why have you decided to switch ?

Byte Commander

Or does anyone know how I could listen for output lines of a command in Bash and execute a command once the last event was 2 seconds ago?

Because as it currently is, I only support single and double tap.

Stefano Palazzo

11:03 AM

@ByteCommander You can probably do it with expect but that's so complicated...

Serg

Personally I'd use timestamp difference

Byte Commander

And more important, the single tap command will also be executed if I tap again right after it.

terdon

@Serg Weren't you going to bed? Do I need to kick you?

grooveplex

When editing files with Git I sometimes forget it's okay to commit changes that are less than 6 characters xD

Byte Commander

@Serg does not prevent execution of single-tap command always before the double tap one.

terdon

11:04 AM

Maybe a mod message: "This user is currently suspended to get some sleep. The suspension ends in 8 hours"

5

Serg

It's cool, it's cool. I'm going :D

Byte Commander

I would actually need some kind of multithreading in Bash here...

Serg

@ByteCommander keep me posted, I'm interested in this script

Byte Commander

okay, will do :)

grooveplex

If @ByteCommander changes it into a repo, you could star and watch it

Byte Commander

11:07 AM

it is a repo already.

github.com/au-answers/UniversalPowerButton

It's just still empty.

Need to push first.

grooveplex

Woot

It seems like a cool idea

I could launch atom, chromium-browser and filezilla in one tap

Zacharee1

isn't that 2GB total? askubuntu.com/questions/798503/…

Stefano Palazzo

@ByteCommander the au-answers org on github looks kind of official

I'm no expert, but maybe review the trademark guidelines

grooveplex

A lot of @JacobVlijm's scripts would fit in there

Stefano Palazzo

I remember we had to make some changes to the google+ group because of this

stackexchange.com/legal/trademark-guidance

grooveplex

11:10 AM

I shall now go to eat lunch

Jacob Vlijm

@grooveplex thanks! In practice, AU is my script- database. Launchpad for the more advanced stuff.. In the beginning, I kept them locally, but my book-keeping is worse than AU :)

Byte Commander

@StefanoPalazzo Thanks for the hint, I'll read your link...

@StefanoPalazzo I added "Please note this is NO OFFICIAL repository of Ask Ubuntu or Stack Exchange!" to the org's description. That should be enough, I think?

The logo is made by myself and Ask Ubuntu is spelled correctly. I see no issues here.

IanC

good morning

grooveplex

11:30 AM

@ByteCommander aks ubnutu

@IanC o/

:p

IanC

what you guys up to?

grooveplex

@IanC I'm going to review some first posts by new users

Byte Commander

Serg is still here - or again...

IanC

guess I don't have rep to review anything yet

Byte Commander

0

Q: How to count read lines and run command two seconds after last input in Bash?

I want to monitor the output of a command which keeps running infinitely and prints a line every now and then. It displays events of a hardware button and each line indicates a push. My script is supposed to run other commands when it receives lines, but the problem is that not the content of th...

linux multithreading bash

grooveplex

11:36 AM

@IanC Just keep going, suggest good edits to posts, post awesome answers :)

IanC

everytime I see a question that I've the knowledge to answer, it's already answered haha

most are out of my skill set :/

grooveplex

@IanC You'll learn

You might want to fix this one up, fix the grammar, make it readable, while preserving the question askubuntu.com/questions/798358/…

If you do your best, you'll get +2 rep.

IanC

I'll suggest an edit :)

grooveplex

That's what got me started and now I'm hooked.

IanC

man, I have a blockage to write I with lowcase

grooveplex

11:44 AM

This one needs some love too (and isn't as bad) askubuntu.com/posts/798521/edit @IanC

IanC

the idea is just to correct the grammar stuff or take stuff that is out of context too?

grooveplex

Just remove anything irrelevant

That's what I do

askubuntu.com/posts/798491/edit too, @IanC

IanC

like 'this is a good netbook'?

lol

grooveplex

delete it

Stefano Palazzo

@ByteCommander I can't say yes or no of course. I would be surprised if there are still any issues now.

thumbsup

Byte Commander

11:49 AM

:)

Thomas W.

good morning

IanC

good morning @ThomasW.

@grooveplex, I edited the first one, what do you think?

grooveplex

Now it's placed in a queue and users with enough reputation will approve it

This takes time

But I see the edit button is greyed out for me, so another edit (yours) is pending approval. In the mean time, you can fix askubuntu.com/posts/798521/edit and askubuntu.com/posts/798491/edit

@IanC

Thomas W.

coughs

i don't think it's 'pending' no more

IanC

@ThomasW., we were talking about internet security yesterday. Man, I got scared how unsafe some website authentications are

Thomas W.

11:53 AM

that said, that one could be better written, IMO. Just not awake enough to edit it :P

@IanC welcome to the world of poor web applications

sites I don't trust I never give them a good password

randomgenerated all the way :P