Cannot open graphical application through command line? - bash

I am having trouble opening graphical applications in linux (Sublime Text 2 in this case) through the terminal. I am using Fedora 17. I get this error for other graphical applications that I try to open up through the command line as well.
[root#computer djproject]# sublime settings.py
No protocol specified
(sublime:4202): Gtk-WARNING **: cannot open display: :0
Also, I get the same type of error when I try to do:
sudo sublime
Note in the command above I was logged in as a regular user without root access. Also 'sublime' is mapped to Sublime Text 2, and I have tested it before in other scenarios, so it is not the problem. Also, I have set this particular user up as a valid sudoer and the sudo command also works in other cases.
While researching the problem I came across many similar cases with no clear solution.
The following link has a user with a similar problem (although using ssh and on Ubuntu, rather than local and Fedora in my case).
Thanks in advance!

I spent quite a lot of time trying to figure this problem out, and came across this thread as I found a fix.
My problem was simply that I was running my commands from within the byobu session. I opened a new terminal tab and successfully ran the same commands.

Since DISPLAY is being defined, this may be a problem with permissions. How are you starting X? (As far as I know normally X is started by root and when you login you are granted access such that these issues don't occur, unless you're running sudo from a different account than the one you're logged into X with.)
You need to provide the correct 'cookie' file to access the session (simply being root isn't enough to get in). For users this is normally ~/.Xauthority, so executing xauth merge /home/<user>/.Xauthority should do the trick.
Alternatively have you tried gksu?

I actually needed this (run an X application from CLI with a different user), and valid workarround is to SSH -X:
user1 owns X
user2 is the second user that wants to run an X program from CLI, in this example, eclipse ide
user1:~$ ssh -X user2#localhost
The authenticity of host 'localhost (127.0.0.1)' can't be established.
ECDSA key fingerprint is
Are you sure you want to continue connecting (yes/no)? yes
Warning: Permanently added 'localhost' (ECDSA) to the list of known hosts.
user2#localhost's password:
Welcome to Ubuntu 14.04.1 LTS (GNU/Linux 3.13.0-44-generic x86_64)
user2:~$
user2:~$ /opt/eclipse/eclipse

I know this is 5 years old post, but I spend much time to solve issue like this on installation of Renderman of Pixar. Then I like to send my solution that maybe helps someone else
The problem is because of this "sudoer (here root) has no access to graphical space". (I don't know it is always or sometimes. I faced this issue on Ubuntu 16.04)
Doing the following solved my issue:
first, start Terminal as graphical user, Alt+Ctrl+T
then, execute these lines
$ unset XAUTHORITY
$ xhost add $DISPLAY . 123f
$ xhost +local:all
$ sudo xclock # or any graphical program needs sudoer
Let me know your feedbacks

Related

ssh-add not saving identity after reboot - continues to fail after editing config file and trying numerous flag options

I have tried numerous options to add my ssh key for bitbucket to no avail.
When I reboot it ssh-add -L it says The agent has no identities.
I have tried using the following guides to add my ssh-key:
https://docs.github.com/en/authentication/connecting-to-github-with-ssh/generating-a-new-ssh-key-and-adding-it-to-the-ssh-agent
https://support.atlassian.com/bitbucket-cloud/docs/set-up-an-ssh-key/
I have tried several configurations of my config file including the following:
From BitBucket docs
Host *
UseKeychain yes
From Github docs
Host *
AddKeysToAgent yes
UseKeychain yes
IdentityFile ~/.ssh/bitbucket
I tried using ssh-add -K ~/.ssh/bitbucket and ssh-add --apple-use-keychain ~/.ssh/bitbucket
I tried starting the agent 2 different ways
From BitBucket docs
eval `ssh-agent`
From GitHub Docs
eval "$(ssh-agent -s)"
When I run it, it works until I reboot. Sometimes it doesn't work when I switch terminals or use git operations in VSCode.
On reboot nothing works.
Looking for any solutions
I'm guessing from:
--apple-use-keychain
that you're on macOS (I added that to the tags). This matches up with another part of your question:
Sometimes it doesn't work when I switch terminals ...
There are two tricky bits that intertwine here:
It's possible to have more than one ssh-agent running (but generally you don't want this).
On macOS, when you boot up the system and log in—even before any Terminal windows open up—the system has started one ssh agent for you.
This second bullet point is specific to macOS. On other systems, it's usually the case that the system has not started an agent for you, and therefore you must start one. But on macOS the system has started one for you. You don't want to start a second one! So do not run eval `ssh-agent`.
If you do run it, you get a second agent, as requested, and then only that one Terminal window can talk to that agent. This results in other Terminal windows not working, as you observed, and could lead to other similar issues like the VSCode one, perhaps. (I don't use VSCode so this part is just a guess.)
You do have to run:
ssh-add ~/.ssh/bitbucket
or similar at least once; I do it after each reboot, to load the key into the agent. According to this question on apple.stackexchange.com, using -K will save the passphrase for the key, and on Sierra or later you must take an extra step as well; see that question and its answer for more.
(I switch OSes a lot so I tend to avoid depending too much on any one particular OS's features. The trick with Terminal and ssh-agent is actually kind of annoying, in that respect. 😀 But it is useful.)

slapd command on MacOS

I have the following commands on MacOS
$ sl
slapacl slapadd slapauth slapcat slapconfig slapdn
slapindex slappasswd slapschema slaptest sleep slogin
I am following this tutorial on running an ldap server on MacOS:
http://krypted.com/mac-security/starting-openldap-on-mac-os-x-client/
seems strange that I don't have a slapd command - anyone know why?
Since slapd is almost never run "by hand", it's not in one of the binaries directories that're in the default PATH. Instead, it's in /usr/libexec, which is the usual place for things that're run automatically rather than manually. So run it with sudo /usr/libexec/slapd instead of just as slapd. (BTW, the sudo is needed so it can allocate low-numbererd TCP ports, and get full access to its database).

Jenkins on OSX gets a identity crisis

I have Jenkins running on OSX 10.8.2. I will often leave a session logged in and su'd into the Jenkins account.
On occasion I will get a cryptic call/email/text from a socially inept user who say simply that "Jenkins is broken" and attaches a useless log snippet indicating that Jenkins could not talk to a remote host because the keys were invalid. The Jenkins build fails. The first thing I do is a "whoami" on the session I'm logged into.
whoami -> _assetcache
I type "exit"
whoami -> root
sudo su - jenkins
whoami -> jenkins
What causes it to think the user has become _assetcache? Why is it fixed by simply logging back into the account? When I check ownership on the jenkins user files they show _assetserver for the user and group too, but logging out and back in seems to clear the issue every time. Any idea what may be causing the issue?
Thanks
I would still like to know what causes this, but I have a hack that addresses the issue and for whatever reason, as strange as it may seem, it works:
As root I run a cron script once a hour that executes: sudo su - jenkins
I don't consider the problem solved, but at least that's a workaround. Longer term, I'm recommending that we simply move off the OSX platform and onto a AWS platform.

How to Connect to localhost with SSH(PuTTy)

I just figured how to connect to my webhost with PuTTy .
But how to I connect to my localhost? I put
Servername: localhost
port: 22 (I've tried 80 too)
And it gives me an error "failed to connect"
How do I connect?
If you are using Cygwin on your local host, you can connect to Cygwin's sshd (SSH Daemon).
3 easy commands to install the sshd as a service: (always there when you startup the machine)
$ ssh-host-config -y # enable sshd. "-y" answers yes to all queries.
$ cygrunsrv --start sshd # start it as an autostart Windows service
$ ssh localhost # try to recursively log in via ssh
Taken from: http://nfnaaron.posterous.com/tag/puttycyg#Section2
(The second approach)
=> You get the entire ssh infrastructure: public key authentication, ssh-agent, etc...
Ensure that you have running a SSH server (such as openssh-server) running on localhost and not just a web server (such as apache). Also ensure, that localhost is really mapping to 127.0.0.0/8
The solution in the answer above won't work unless you have installed Cygwin with the OpenSSH package selected - you have to do this manually during the installation process (see option a below).
Depending on the intended purpose of your connection you can try one of the options below, option (b) being much easier to install but lacking the *nix shell capabilities.
a. You can install a Cygwin shell with ssh server, this site (http://ist.uwaterloo.ca/~kscully/CygwinSSHD_W2K3.html) has instructions for Windows Server but they work for other Windows too with may be some of the questions shown in the output on the page not appearing on non-server version of Windows. Also, where it says in the instructions to issue the command:
mount -s --change-cygdrive-prefix /
delete the -s option so that the command is
mount --change-cygdrive-prefix /
(at least this was the case for me on Windows 7).
b. PuTTy site suggests WinSSHD (http://www.bitvise.com/winsshd-download). It's an easy self-installer. Once it's up you have to click onthe StartSSHD link about 1/3rd of the screen down on the first page of the config window. Then you can connect your PuTTy to localhost. However, in my experience, it didn't provide any *nix command support, only the native Windows ones and I couldn't find anything in their user guide on this.
Hope this helps.
Just adding this answer in case anyone is still looking for a solution.
In your hostname (or IP address) section, enter localhost or 127.0.0.1
Leave the port to its default value 22
Click on open
Now a login shell will popup -
Log in as your username, your username is basically what you get when you type whoami in your Terminal.
In the password section, type the password that you use as your system's password.
The above steps should connect localhost with ssh(PuTTY)

SSH hangs on Mac Book Pro; AFS and Network Preferences?

I am having an issue with SSH hanging on my Mac Book Pro. This only happens to me once I get home from work after I have used SSH while at work. The three factors I have narrowed the issue down to are SSH, our work AFS network drive and the method of network connectivity.
At work we use an AFS drive with Kerberos Authentication to do all of our software development work on. I authenticate with Kerberos in order to gain access to the AFS drive where all my source code lives, but I open a local editor (Eclipse) which references the files on the AFS drive. Whenever I need to compile my code, I SSH in to my development server (which is also authenticated to the AFS drive) and compile from there. (Sanity Note: I know that it is a super wacky setup, but I promise I had NOTHING to do with it. I'm just making do with what I've got.)
For my Network Preferences, I use the Automatic location all the time. For that configuration I have Built-in Ethernet en1 configured to use DHCP and our company's DNS server for when I'm at work (there is no wireless available). When I go home I connect to my home network via wireless, again using DHCP.
I have a hunch that the AFS connection/Ethernet configuration is somehow the culprit here. Restarting the SSH daemon doesn't correct the problem. The only way I have found to correct the issue is by restarting the computer each time I want to use SSH. Keep in mind that I have no other (known) networking issues while at home after I've had the laptop at work.
I have a co-worker who has reported to me the same issue on his MBP.
I'm truly stumped on this one. Please provide some guidance. Thanks!
Can you be more specific about "SSH hanging"?
It sounds like your ssh client hangs after losing the connection and you are unable to do anything in the terminal. To get around this, you can use the ssh escape character (default: ‘~’) to begin an escape sequence, and use the the '.' to terminate the connection.
You can get a list of other ssh escape sequences using ~?, here's the one for OpenSSH SSH client:
Supported escape sequences:
~. - terminate connection
~B - send a BREAK to the remote system
~C - open a command line
~R - Request rekey (SSH protocol 2 only)
~^Z - suspend ssh
~# - list forwarded connections
~& - background ssh (when waiting for connections to terminate)
~? - this message
~~ - send the escape character by typing it twice
(Note that escapes are only recognized immediately after newline.)
If typing ~. does not work, it could be that you have the escape character disabled, in which case you can put
EscapeChar ~
inside ~/.ssh/config or /etc/ssh_config
Even when the escape character is disabled, you can simply pull up another Terminal window and type
killall ssh
to end all running ssh processes, allowing you to connect out again.
Restarting the SSH daemon would not correct this problem because sshd allows other clients to connect in to your machine, and does not affect your ssh clients connecting out to some other machine.
It appears that the fix for my issue is to delete my Kerberos tokens that are valid while at work, but not valid when at home. Hope this can help anyone having a similar issue.
Just a shot in the dark:
I recently had problems using ssh after installing Rogue Amoeba Audio Hijack Pro.
I could only use ssh as super user (sudo).
An Update to 2.8.1 resolved the issue...
Also see http://www.macobserver.com/article/2008/03/19.8.shtml for the issue.

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