Ubuntu Tips

bashrc prompt

 case "$TERM" in
 xterm*|rxvt*)
   PS1="\u@\h:\W$ "
   ;;
 *)
 ;;
 esac

Run Levels

runlevel
 
telinit 3

Install

• Package search

 sudo aptitude search phidget

Each search result is listed on a separate line.

• The first character of each line indicates the current state of the package:
  • p, no trace of the package exists on the system,
  • c, the package was deleted but its configuration files remain on the system,
  • i, the package is installed, and
  • v, the package is virtual.
• The second character indicates the stored action (if any; otherwise a blank space is displayed) to be performed on the package,
  • i, the package will be installed,
  • d, the package will be deleted, and
  • p, the package and its configuration files will be removed.
• If the third character is
  • A, the package was automatically installed.

The follow provides some of the above info

 apt-cache search opencv

• Detailed description of a package

 apt-cache show opencv-do

• List the files in a package

 dpkg -L opencv-doc

• Find the package a file is in

 dpkg -S highgui.h

• Remove unneeded packages

 apt-get auto remove

• Get source

 apt-get source phidget

Update

 sudo apt-get update
 
 sudo apt-get dist-upgrade

See also the Software Updater in Preferences menu

Text Mode for Ubuntu 14.04

Reference

Boot Into Text Mode

Text Mode Login

Setup for text boot. First backup the grub file.

 cd /etc/default/
 sudo cp -n grub grub.org

Edit the grub file reflect these changes as shown by diff.

 diff grub.org grub
   11,12c11,12
   < GRUB_CMDLINE_LINUX_DEFAULT="quiet splash"
   < GRUB_CMDLINE_LINUX=""
   ---
   > # GRUB_CMDLINE_LINUX_DEFAULT="quiet splash"
   > GRUB_CMDLINE_LINUX="text"
   20c20
   < #GRUB_TERMINAL=console
   ---
   > GRUB_TERMINAL=console

Update grub

 sudo update-grub

Start up X

To start X in this boot session:

 service lightdm start

To Revert

Revert to X boot.

 cd /etc/default/
 sudo cp grub.orig grub
 sudo update-grub

Text Mode for Ubuntu 10.04

Reference: Modify Ubuntu for text mode

• Edit /etc/init/rc-sysint.conf

 diff rc-sysinit.conf rc-sysinit.conf.org 
 14c14
 < env DEFAULT_RUNLEVEL=3
 ---
 > env DEFAULT_RUNLEVEL=2

• Edit /etc/init/gdm.cong

 root@tabor:init# diff gdm.conf gdm.conf.org 
 13d12
 <           and runlevel[!3]

The result in gdm.conf should be:

 start on (filesystem
         and started dbus
         and (drm-device-added card0 PRIMARY_DEVICE_FOR_DISPLAY=1
              or stopped udevtrigger))
         and runlevel[!3]
 stop on runlevel [016]

Warning: Don't have an SD card connected to the USB port - maybe it tried to boot from it?

To get it going in X.

startx

Virtual Consoles

Virtual Consoles

• Ctrl+Alt+F1 to F6 are the virtual consoles provided by the getty/agetty programs.
• Ctrl+Alt+F7 is the console where your X server is running. The GUI (Gnome/KDE or any other) runs over X.

Won't Boot

Boot from the 10.04 Install CD.

 sudo mkdir /media/tmp
 mount /dev/sda1 /media/tmp
 cd /media/tmp/etc                      fix things

ssh

• OpenSSH Server set up

Two ways to start service

 sudo /etc/init.d/ssh start
 sudo service ssh start

Two was to stop service

 sudo /etc/init.d/ssh stop
 sudo service ssh stop

Using ssh on Mac

ssh -X eepp@10.0.0.122

on Mac

system load

uptime
top
dstat
cat /proc/loadavg

/proc man

load from wikipedia

change hostname

• Edit /etc/hostname , make the name change, save the file.
• You should also make the same changes in /etc/hosts file.
• Run sudo /etc/init.d/hostname restart or sudo service hostname restart. (There is no hostname init script so I rebooted.)
• change name

Printing

Something like:

• Preferences -> Printers
• Add
• Device first expand Network Printer
• Device choose Network Printer
• Enter 10.0.0.3 as Host and press find

Also install ascii 2 ps

 sudo apt-get install a2ps

print 1 column, landscape, line count every 5 lines, 132 char per line

 a2ps --columns=1 -r -C -l 132

find

 find /opt/ros/jade/ -name *.so -exec grep CamShift "{}" ";"

usb udev

Locate the devices that need permission set

 lsusb
   Bus 002 Device 009: ID 16c0:0483 Van Ooijen Technische Informatica Teensyduino Serial
   Bus 002 Device 008: ID 046d:c216 Logitech, Inc. Dual Action Gamepad
   Bus 002 Device 002: ID 046d:0805 Logitech, Inc. Webcam C300

Create the following rules file.

 cat /etc/udev/rules.d/95-floor-hugger.rules
 
   # Logitech, Inc. Webcam C300
   SUBSYSTEMS=="usb", ACTION=="add", ATTRS{idVendor}=="046d", ATTRS{idProduct}=="0805", MODE="666"
 
   # Logitech, Inc. Dual Action Gamepad
   SUBSYSTEMS=="usb", ACTION=="add", ATTRS{idVendor}=="046d", ATTRS{idProduct}=="c216", MODE="666"
 
   # Van Ooijen Technische Informatica Teensyduino Serial
   SUBSYSTEMS=="usb", ACTION=="add", ATTRS{idVendor}=="16c0", ATTRS{idProduct}=="0483", MODE="666"

Hardware Info

 sudo apt-get install hardinfo
 hardinfo&

or

 lspci -nnk | grep net -A2

or

 lshw

Logs

 dmesg

 /var/log/boot.log

Links

man pages