Steve Lorimer's questions

I am trying to save a web page I am viewing in Chrome using CtrlS (Save As) and using the default "webpage complete" option.

I can view the web page perfectly fine in the browser.

However, the save operation runs at an absolute crawl and doesn't ever complete, and often times out.

When I do the exact same operation in Firefox the save happens instantaneously.

I tried looking at the Network tab in Chrome Developer Tools, but nothing appeared when I started the save operation, which is even more puzzling to me.

I am not running an ad-blocker, as the site has ad-blocker detection and won't function with ad-blocking enabled.

• What is happening here?
• Could some javascript "anti-save" script be the cause?
• How can I save the webpage in Chrome?

I'm finding it difficult to find reliable up-to-date information on how networking configuration is managed on Ubuntu 18.04 workstation.

I believe in 16.04 dnsmasq was the new kid on the block, and it took over duties from resolved

I recently found out about netplan though. This link refers to netplan for managing DNS, but it seems to only really apply to ubuntu-server, as the netplan configuration file on my workstation offloads everything to NetworkManager:

$ cat  /etc/netplan/01-network-manager-all.yaml 
# Let NetworkManager manage all devices on this system
network:
  version: 2
  renderer: NetworkManager

I guess I'm just confused as to what is responsible for what, there is a lot of confusing information about ifupdown, resolved, dnsmasq, netplan, nm, etc.

How can I get reliable, up-to-date information on whatever the state-of-the-art is for all things networking in Ubuntu 18.04?

I use meld for graphical diff comparisons.

I would like to associate .tpp as a C++ source file for syntax highlighting purposes.

How do I do this?

I've recently installed Kubuntu 18.04.

I've found that CtrlTab doesn't switch between tabs in the current application.

I've gone to System Settings -> Shortcuts -> Global Shortcuts -> KWin

• For "Walk Through Window Tabs" I've specified shortcut Ctrl+Tab
• For "Walk Through Window Tabs (Reverse)" I've specified shortcut Ctrl+Shift+Tab

This doesn't seem to work.

How can I enable this behaviour?

I have a Qt app which statically links against protobuf 2.6.

When I try to run it on Ubuntu 17.10, I get an exception on startup.

[libprotobuf FATAL google/protobuf/stubs/common.cc:61] This program requires 
version 3.0.0 of the Protocol Buffer runtime library, but the installed version
 is 2.6.1.  

Please update your library.  

If you compiled the program yourself, make sure that your headers are from the 
same version of Protocol Buffers as your link-time library.  

(Version verification failed in "/build/mir-y44crS/mir-0.28.0+17.10.20171011.1/
 obj-x86_64-linux-gnu/src/protobuf/mir_protobuf.pb.cc".)

Looking at a stack trace, I see that the source of the exception is a protobuf file called mir_protobuf.pb.cc in libmirprotobuf.so.3

#8  google::protobuf::internal::VerifyVersion (headerVersion=3000000, minLibraryVersion=<optimized out>, filename=0x7f56e740fb00 "/build/mir-y44crS/mir-0.28.0+17.10.20171011.1/obj-x86_64-linux-gnu/src/protobuf/mir_protobuf.pb.cc") at google/protobuf/stubs/common.cc:61
#9  0x00007f56e73dd2bb in mir::protobuf::protobuf_AddDesc_mir_5fprotobuf_2eproto() () from /usr/lib/x86_64-linux-gnu/libmirprotobuf.so.3
#10 0x00007f56e73d0109 in ?? () from /usr/lib/x86_64-linux-gnu/libmirprotobuf.so.3

Deeper in the stack trace I see this is being called by Qt, via libqgtk3.so

#16 0x00007f56f9cde0d9 in _dl_open (file=0x55c572496638 "/usr/lib/x86_64-linux-gnu/qt5/plugins/platformthemes/libqgtk3.so", mode=-2147479551, caller_dlopen=0x7f56f840571c, nsid=-2, argc=<optimized out>, argv=<optimized out>, env=0x7ffe60c11c38) at dl-open.c:660
...
#23 0x00007f56f83ef068 in QFactoryLoader::instance(int) const () from /usr/lib/x86_64-linux-gnu/libQt5Core.so.5

protobuf 3 is installed by default on Ubuntu 17.10

libmirprotobuf3/artful,now 0.28.0+17.10.20171011.1-0ubuntu1 amd64 [installed,automatic]
libprotobuf-dev/artful,now 3.0.0-9ubuntu5 amd64 [installed]
libprotobuf-lite10/artful,now 3.0.0-9ubuntu5 amd64 [installed,automatic]
libprotobuf10/artful,now 3.0.0-9ubuntu5 amd64 [installed,automatic]

My app is statically linking against protobuf 2.6, but it seems this is interfering with libmirprotobuf.so.3.

Is it possible to run my app on Ubuntu 17.10?

According to this answer, I can disable apport by editing /etc/default/apport and setting enabled=0.

I have done this:

$ cat /etc/default/apport
# set this to 0 to disable apport, or to 1 to enable it
# you can temporarily override this with
# sudo service apport start force_start=1
enabled=0

In fact, you can see I actually did this in December 2016:

$ stat /etc/default/apport
  File: '/etc/default/apport'
...
Modify: 2016-12-22 09:43:01.688938268 -0500
...

Recently I noticed apport was running, so I stopped it and, then rebooted to see if it would come back again

$ sudo service apport stop
$ sudo reboot

However, on startup, it is indeed active again:

$ service apport status
● apport.service - LSB: automatic crash report generation
   Loaded: loaded (/etc/init.d/apport; bad; vendor preset: enabled)
   Active: active (exited) since Tue 2017-07-18 11:27:44 EST; 45min ago
     Docs: man:systemd-sysv-generator(8)
  Process: 1395 ExecStart=/etc/init.d/apport start (code=exited, status=0/SUCCESS)

Jul 18 11:27:44 foobar systemd[1]: Starting LSB: automatic crash report generation...
Jul 18 11:27:44 foobar systemd[1]: Started LSB: automatic crash report generation.

You can see I rebooted my machine at 11:27, so apport is being started at startup

$ sudo last reboot
reboot   system boot  4.4.0-83-generic Tue Jul 18 11:27   still running

How can I permanently disable apport?

I am trying to connect from an Ubuntu 16.04 workstation to another Ubuntu 16.04 workstation on my local LAN.

I have enabled Desktop Sharing as per the official documentation.

I have no confirmation required, no password required, and allow others to control your desktop. The machine is only accessible on my LAN.

There is no mention of how to connect to the desktop once you have enabled it.

I tried using the default installed Remmina Remote Desktop Client, and have tried both VNC and RDP. Neither works.

I have confirmed access, as I am able to ssh to the remote instance.

How can I connect to my remote desktop?

I have recently upgraded my dev machine to Ubuntu 16.04 (fresh install, wiped 14.04)

The default version of gcc is gcc-5.3.1.

A problem that I have is a vendor supplied library is only built using gcc-4.9, which is not compatible with gcc-5.

I have asked the vendor to provide a new version of the library, but it is unlikely that that will happen any time soon.

In the meantime I have installed gcc-4.9.3 from Ubuntu's package repos.

I now have both gcc-4.9 and gcc-5 installed:

ls -l /usr/bin/gcc*
lrwxrwxrwx 1 root root      5 May  9 11:49 /usr/bin/gcc -> gcc-5
-rwxr-xr-x 1 root root 838008 Apr 13 23:23 /usr/bin/gcc-4.9
-rwxr-xr-x 1 root root 915704 Apr 13 11:29 /usr/bin/gcc-5

I tried to build our source with gcc-4.9, but now I come up against the same ABI issues, but going the other way.

The problem I have is that we have a bunch of dependencies which we would typically install from the distro packages

sudo apt-get install \
    python-dev \
    libbz2-dev \
    libboost-all-dev \
    libprotobuf-dev \
    libgoogle-perftools-dev \
    postgresql \
    libpqxx-dev

Whilst I can configure my build to use gcc-4.9

mkdir build && cd build
CC=/usr/bin/gcc-4.9 CXX=/usr/bin/g++-4.9 cmake ..
make -j8

I now get linker errors when linking against libtcmalloc_minimal.a, libprotobuf.a etc.

So the next step that I tried was to remove all the dependencies installed from the distro repos and start building the dependencies from source.

CC=/usr/bin/gcc-4.9 CXX=/usr/bin/g++-4.9 ./configure
make -j8
sudo make install

The problem here is that I'm starting to head down a rabbit-hole. Each dependency has other dependencies, and I'm not sure where it's going to end.

The other option is to downgrade back to Ubuntu 14.04 or some version which ships with gcc-4.9 instead of gcc-5.

Before I try this thurmonuclear option, I was wondering if there's a better way to do this?

Maybe it's possible to install from repos built with gcc-4.9, or some other way?

KDE's Dolphin file manager has an integrated terminal

Changing directory in the terminal also changes the directory displayed in the file manager.

Is there an Ubunty Unity or Gnome equivalent?

My home internet connection has a static IP address (eg: 123.123.123.123)

I have configured my router to forward port 9000 to an internal host (192.168.1.101), which is running Ubuntu 14-04.

I run netcat listening on port 9000:

$ nc -l 9000

Connecting from inside my LAN:

On another machine on my LAN I can telnet to that port:

$ telnet 192.168.1.101 9000
Trying 192.168.1.101...
Connected to 192.168.1.101.
Escape character is '^]'.
hello world

and the connection succeeds

$ nc -l 9000
hello world

Connecting from outside my LAN:

However, if I try to connect via my external IP address I cannot get through:

$ telnet 123.213.123.123 9000
Trying 123.213.123.123...

Firewall issue?

I tried to allow port 9000 on iptables (I am no expert on iptables btw!):

$ sudo iptables -I INPUT 1 -p tcp --dport 9000 -j ACCEPT

This is my resulting configuration:

$ sudo iptables -L -n -v
Chain INPUT (policy ACCEPT 203 packets, 16977 bytes)
 pkts bytes target     prot opt in     out     source               destination         
    0     0 ACCEPT     tcp  --  *      *       0.0.0.0/0            0.0.0.0/0            tcp dpt:9000

Chain FORWARD (policy ACCEPT 0 packets, 0 bytes)
 pkts bytes target     prot opt in     out     source               destination         

Chain OUTPUT (policy ACCEPT 178 packets, 23749 bytes)
 pkts bytes target     prot opt in     out     source               destination         

telnet still can't get through.

I think the iptables config might be unnecessary anyway though, because ufw status says it's inactive:

$ sudo ufw status
Status: inactive

Port scanning says it's open:

If I run a port scanner on my external IP with nc -l 9000 running it says the port is open.

If I run tcpdump I can't see anything coming in on port 9000 when I try telnet to the port. However, running the port scanner does show up:

18:41:34.023692 IP 198.199.98.246.49977 > my_host.9000: Flags [S], seq 3955039481, win 14600, options [mss 1400,sackOK,TS val 4051434607 ecr 0,nop,wscale 8], length 0
18:41:34.023748 IP my_host.9000 > 198.199.98.246.49977: Flags [S.], seq 3541700333, ack 3955039482, win 28960, options [mss 1460,sackOK,TS val 465840988 ecr 4051434607,nop,wscale 7], length 0
18:41:34.250110 IP 198.199.98.246.49977 > my_host.9000: Flags [.], ack 1, win 58, options [nop,nop,TS val 4051434663 ecr 465840988], length 0
18:41:34.250973 IP 198.199.98.246.49977 > my_host.9000: Flags [F.], seq 1, ack 1, win 58, options [nop,nop,TS val 4051434664 ecr 465840988], length 0
18:41:34.251035 IP my_host.9000 > 198.199.98.246.49977: Flags [F.], seq 1, ack 2, win 227, options [nop,nop,TS val 465841045 ecr 4051434664], length 0
18:41:34.477197 IP 198.199.98.246.49977 > my_host.9000: Flags [.], ack 2, win 58, options [nop,nop,TS val 4051434720 ecr 465841045], length 0

Questions:

I'm at a bit of a loss as to where the problem is.

• How can I diagnose where the issue is?
• How come the port scan data comes through, but not my telnet?
• How can I allow incoming connections?

I'm running a local IPython notebook server. (IPython version 1.2.1).

Running the notebook under Chrome means the keyboard shortcuts don't work. (Chrome version 36.0.1985.125)

Running under Firefox works (Firefox version 31.0).

Is there any way I can get IPython notebook keyboard shortcuts working in Chrome / Ubuntu?

I have an nfs share I'm trying to mount automatically at startup in ubuntu / xbmc

I have the following in /etc/fstab

nas:/mnt/raid /mnt/raid nfs noauto,rw,async

On startup the mount doesn't automatically occur.

If I issue a manual mount command it works:

$ sudo mount -o noauto,rw,async -t nfs nas:/mnt/raid /mnt/raid

How can I get this mount to occur automatically on startup?

Looking for errors in /var/log/messages doesn't yield much, but it does say something about nodiskmount:

Kernel command line: \
    BOOT_IMAGE=/boot/vmlinuz-2.6.32-29-generic \
    root=UUID=e575a39a-09d9-4747-befa-466c7aae64d1 \
    ro quiet splash \
    xbmc=autostart,nodiskmount \                       <-- THIS LINE
    loglevel=0 \
    video=vesafb

Could this be the problem? Is there any way to disable nodiskmount?

I am using the XBMCFreak LiveCD 10 from XBMCFreak.nl which is based on Ubuntu lucid lynx

$ lsb_release -a
No LSB modules are available.
Distributor ID: Ubuntu
Description:    Ubuntu 10.04.2 LTS - XBMCLive
Release:    10.04
Codename:   lucid