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.
Related
I just accidentally typed stop instead of exit in a bash script. When I execute it my Xubuntu went to the login screen and when I logged in, everything was closed and it was like I just started the computer.
I then went to my Ubuntu on a virtual box and executed stop in the terminal. Then some windows was closed and some frames around other windows disappeared.
I'm a Linux noob but when I looked at the stop command info it looks like you need to have an argument to use the stop command.
Is this just a bug or is this supposed to happen? If it's supposed, then I'm really curious of whats happening. My guessing is that it will try to kill all ongoing processes.
I'm new here so I hope this it not a stupid question and its really hard to google on a common word like stop :/
man stop should tell you what it does. E.G. http://manpages.ubuntu.com/manpages/precise/en/man8/stop.8.html
I think it should tell you it needs an argument for a name of a job to stop.
However it appears from what you describe that it's stopping the X11 window manager?
I need to run a shell script that should interact with couple of servers / routers in daily schedule. The script will simply login to the remote end, run a command. Up to here i hear that you are saying it is easy. The real problem here is that i need to analyze the output of the first command and based on the output i need to organize the second command. This is also doable, but the situation here is that i do not want to login and logout from the box for every command.
What i need is to login once, stay alive ,run the command take the output, analyze it and then run the second command later on logout and close connection.
Correct me if i am wrong but expect is not an option here. I want to ask for your suggestions.
Which language / module of this language i can use to complete this requirement.
Environment is not pure ssh, so i should have something general that can be used for both ssh/telnet.
Thanks in advance
Since you mentioned python, pexpect should do the job pretty well:
https://pexpect.readthedocs.org/en/latest/overview.html
I am on windows machine, when I temporarily change to console using :sh then back to vim with exit command and then again back to console and it starts over. this causes me to lose my previous directory. Is there other way returning back to vim won't start the shell over?
Not really
https://stackoverflow.com/a/12089631/1427295
GVIM does not retain a "handle" to the shell that launched it in a way
that allows it to send commands back to it. Because of they
synchronous execution, you also cannot launch a shell from GVIM, keep
feeding it commands while also continue working in GVIM.
I'm afraid you have to use the functionality of your window manager to
launch (and then later re-activate) a shell window, and send the
commands as keystrokes to it. On Windows, this can be done (e.g. in
VBScript) via WshShell's Run(), AppActivate() and SendKeys() methods;
there are probably similar mechanisms for window control on Linux,
too.
If you don't mind having that shell inside your GVIM (emulated, with
all its drawbacks), though, there are plugins that enable that.
https://serverfault.com/a/95405
The Windows command interpreter ("cmd.exe") doesn't provide any
support for saving/exporting/keeping history, of, if it does,
Microsoft didn't document it and nobody was ever able to find it. You
can of course try to work around that, like Sean suggested, but
there's (or does appear to be) no built-in support for this
You may be able to output your command history using echo %cd% > prev_dir.txt then create a script that cds to the directory in prev_dir.txt, but you'd still have to remember to save your directory to the file before you exit the shell each time.
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.
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