EDIT, the question might have not been totally clear, short version:
How to popup a dialog asking for user input if the script is running in the background and not in an active console?
/EDIT
When I run a bash script from udev or cron, it usually runs quietly somewhere in the background. Example could be plugging in an external harddrive runs rsync for data backup. So not every time I plug in the harddrive do I want to launch this action.
What is the most minimal way to fire up some user input dialog and ask yes or no? I could write some interface with PyQt but I want as little dependencies as possible, ideally cross window manager and maybe even without window manager.
Thanks!
EDIT 2: The lightweight (and hence as ugly as expected) version is xmessage, this would probably be the answer to the question, unless you have a better one:
xmessage "Do you want to run the backup script?" -buttons yes,no
http://linux.byexamples.com/archives/87/using-gui-dialog-box/
EDIT: So there's KDialog for kde, is there something really lightweight for X?
http://www.linux-magazine.com/Issues/2009/99/Zenity-and-KDialog
kdialog --title "Do you want to run the backup script?"
--yesno "Do you want to run the backup script?"
I'm currently leaning towards zenity, only trouble is it pulls in a whole array of gtk dependencies on kde, but is cross platform and works on windows. In essence, this is exaclty what I was looking for:
if zenity --question --text="Please press a button."; then
zenity --info --text="You pressed Yes\!"
else
zenity --error --text="You pressed No\!"
fi
But was hoping it would be a lot lighter on the resources / dependencies. Any alternative suggestions?
A simple approach would be for the automated script to simply email you, or perhaps alert with wall with instructions (containing the location of the real script).
Another approach would be for the automated script to touch a file in /var/lib and proceed if the file is still present after 5 minutes. This gives the user the option to stop the process (by removing the file), but maintains some automation.
This is not something you should have cron or udev handling in the first place. Write a userland daemon that listens for the appropriate D-Bus messages and performs the appropriate actions.
This should be post in linux or superuser or serverfault.
But, the number one google search on linux read user input links back here to StackOverflow:
https://www.google.com/search?q=linux+read+user+input&ie=utf-8&oe=utf-8&aq=t&rls=org.mozilla:en-US:official&client=firefox-a&channel=fflb
so I guess it's not too off base.
Again, the third or so google result for linux invoke command usb device plugin links to ServerFault:
https://serverfault.com/questions/399698/execute-a-command-when-a-device-is-connected-via-usb
I'll leave combining those two as an exercise.
Related
I'm new to Linux.Yesterday I wrote some Python codes,now I'm using Linux to execute my codes,it may take a few hours. As my Linux is not native,it's a remote server,I use putty to connect to it.
Now ,I want to close putty and go to sleep.But I don't know how to find my process again and reenter it after I wake up and start putty.And also,I wrote some code to print progress rate，next time when I find the process,can I see the print info again?
Run screen, start your programm and close the connection. After logging in again, use screen -r to resume your session.
Alternatively nohup will do the trick.
screen is the best built-in tool that's always available for that, although it gets a bit weird around keyboard shortcuts, some of which sometimes don't work the way you want exactly.
I've found tmux to be much better in terms of usability.
Alternatively. take a look at mosh, which is trying to replace ssh. It's a mobile shell tool from MIT that supports intermittent connectivity, lots of praise there.
I want a notification in desktop that a particular USB device is inserted.Hence the following is the udev rule.
KERNEL=="sd*",SUBSYSTEMS=="usb",ACTION=="add",RUN+="/home/username/Desktop/notify_script"
notify_script is as follows
#!/bin/sh
su username -c 'notify-send "USB Inserted"'
echo USB_inserted >> /home/username/Desktop/test_file
Problem :
The above script works perfectly if it is executed as root from command line but, notify-send in script is not working if executed from udev.
Question:
How to make notify-send work from udev? or
Is there any other way by which I can achieve notification ?
Is it possible to invoke any GUI from udev?
Thank you.
The main problem is, that the udev-rule will not run in any xorg-related environment per default, thus not knowing which DISPLAY to use. Therefore it will always fail, if You want to echo something into a terminal like a gnome-terminal for example. The script, which shall be executed on the udev-rule-match, must prior to any ui-related execution first export the DISPLAY.
This is done via
export DISPLAY=:0
I assume, that this also will be the problem, and notify-send will just run against the wall.
I am actually also playing with udev-rules, and I managed it to work, though i am acting as root, similar to my answer and this one found already here :
https://unix.stackexchange.com/questions/80882/udev-running-a-shellscript-that-accesses-an-x-display
And also here
Scripts launched from udev do not have DISPLAY access anymore?
You might want also to check zenity. Very helpful for small notifications
I have laptop-desktop setup at home and I have successfully cloned my Archlinux installation from one to another. However, I would like to avoid having to {install all new software, edit settings, update} twice, so I was wondering if it'd be possible to log over ssh from laptop to desktop, do something in terminal and have linux copy everything I type into second terminal with ssh logged in?
Thanks for ideas!
You could type the commands into one terminal then edit ~/.bash_history and save the commands into a script. Copy the script onto the machine with the second terminal and execute it. The advantage of this is now you have a script that saved your setup so you can reuse it whenever you need to.
You can use clusterssh, which duplicates your typed input across multiple systems. It is designed for situations in which the exact same tasks, such as software installation or configuration commands, are needed to be performed exactly the same on multiple systems. See http://sourceforge.net/projects/clusterssh/. Also, the KDE Konsole terminal has similar functionality.
I've noticed that sometimes commands can be tab completed.
e.g. the xm command in xen.
you type xm[space][tab] and it prints out the valid options
which are:
addlabel destroy info network-attach resume sysrq vnet-delete
block-attach dmesg labels network-detach rmlabel top vnet-list
block-detach domid list network-list save trigger vtpm-list
block-list domname loadpolicy new sched-credit unpause
cfgbootpolicy dry-run log pause sched-sedf uptime
console dump-core makepolicy reboot serve vcpu-list
create dumppolicy mem-max rename shutdown vcpu-pin
debug-keys getlabel mem-set resources start vcpu-set
delete help migrate restore suspend vnet-create
That's pretty slick!
How can I implement my own tab command completion in Linux?
This is a pretty broad question, but the general idea is that you register something with the either the compgen or complete builtin. They're both documented in the manual. The previous section documents the general topic of programmable completion, going through how completion attempts are processed.
For a whole ton of examples, see /etc/bash_completion, which provides all the default completion that comes with bash (beyond the totally built-in stuff like filename completion). For even more examples, see anything in /etc/bash_completion.d; those are automatically sourced by /etc/bash_completion as a way of extending the default completion.
This is done via the shell through the use of the GNU Readline library in the case of bash
bash's smart completion is handled by a series of scripted bash functions. On Debian, probably Ubuntu, and maybe other Linux distributions, you can find your system's installed completions in /etc/bash_completion.d.
The official documentation on this mechanism is at http://www.gnu.org/software/bash/manual/bash.html#Programmable-Completion
See this:
How does bash tab completion work?
and this:
http://www.debian-administration.org/articles/316
I am using Putty to connect to a remote server. What I want to know is if there is any way to write my commands and allow them to keep running after I close the session with Putty. The reason for this is that I do not want to keep the computer ON all the time. Is there any way to do this?.
Update with the solution
For my question as it is presented the best solution is use one of the commands provided such as nohup, because you do not have to install any additional software. But if you are in the same problem use screen, install it and use it. It is amazing.
I have selected the answer of Norman Ramsey as favourite because propose several solutions using commands and screen. But please check the other answers specially the one of PEZ, then you get an insight of what screen is able todo.
screen! It's the best thing since sliced bread. (Yeah, I know others have already suggested it, but it's so good the whole world should join in and suggest it too.)
screen is like, like, ummmm ... like using VNC or the like to connect to a GUI destop, but for command shell windows. You can have several shell "windows" open at once in the same screen session. You can do stuff like:
Start a screens session using "screen -dR" (get used to using -dR)
run some commands in one window
press CTRL-A,C to create a new window open a file there in vim
press CTRL-A,0 to go back to the first window and issue some command on the file you just edited
CTRL-A, 1 to go back to your vim session
CTRL-A, C for yet another window and maybe do "sudo - su" (because you just happen to need a full root shell)
CTRL-A, 0 and start a background process
CTRL-A, C to create yet a new window, "tail -f" the log for that background process
CTRL-A, d to disconnect your screen then CTRL-D to disconnect from the server
Go on vacation for three weeks
Log on to the server again and issue "screen -dR" to connect to your existing screen session
check the log in the the fourth window with CTRL-A, 3 (it's like you've been there watching it all the time)
CTRL-A, 1 to pick up that vim session again
I guess you're starting to get the picture now? =)
It's like magic. I've been using screen for longer than I can remember and I'm still totally amazed with how bloody great it is.
EDIT: Just want to mention there's now also tmux. Very much like screen, but has some unique features, splitting the windows being the most prominent one.
nohup, disown, and screen are all good but screen is the best because unlike the other two, screen allows you to disconnect from the remote server, keep everything running, and then reconnect later to see what is happening. With nohup and disown you can't resume interacting.
Try using GNU Screen. It allows you to have several shells open at once. And you can disconnect from those running shells (i.e. close session with Putty) and they will keep doing their thing.
What you are looking for is nohup.
See the wiki link for how to use it.
screen is the best.
Try:
screen -dmS "MyTail" tail -f /var/log/syslog
This start command in background.
Use screen -r to list, and or screen -r Mytail to enter session.
If more users need access same session, use: screen -rx MyTail, and both or more users share the session.
If you can't use screen (because, for instance, your SSH session is being programmatically driven), you can also use daemonize to run the program as a daemon.
One way that works well for me is at.
at works like cron, but for a one-time job. I used it today to download a large file without having to keep my session alive.
for example:
$ at 23:55
at> wget http://file.to.download.com/bigfile.iso
at> ^D
You pass at a time (in the future) and it gives you a prompt. You enter the commands you want to run at that time and hit ctrl+d. You can exit out of your session and it will run the commands at the specified time.
Wikipedia has more info on at.
./command & disown
ssh localhost && ./command && exit