Check the permission of curent directory: ll <file> or ll

• face see the photo

  

Cannot open matlab without sudo: change the owner permission of folder /home/thi/.matlab to thi* (cf. 20)

• Another solution: suppose that matlab is installed on a user’s directory and you have already add this to the $PATH. IT’s only work if you use matlab (not sudo matlab). Then do

sudo env "PATH=$PATH"

from this, you can sudo matlab

Install file .bin, .run

chmod +x file-name.run 
./file-name.run

• Install prerequired packages

  sudo apt-get install cpp freeglut3-dev g++ gcc gfortran
  sudo apt-get install  ghostscript m4 make patch pkg-config wget python
  sudo apt install autoconf
  sudo apt-get install bison
  sudo apt-get install flex
  

• Download freefem++ at here (choose the tar.gz file)
• Extract and cd to the extrated folder

• Run following commands

  autoreconf -i
  ./configure 
  make 
  make check
  sudo make install
  

Download a direct link by terminal

wget <direct-link> -O <name-of-file>.<file-extension>

• Download as usual without terminal by a web browser
• Open Downloads windows of the browser and then copy the download link.
• Stop the download process
• Use the command link in 33 where <direct-link> is the link copied above.

Remove

rm <file>
rm -f <file> # force to remove
rm -rf <dir> # remove folder and files includes
rmdir <empty-dir> # remove empty directories

Check size of a folder

du -hs <directory>

• “h” : human readable (6.7G)
• ”s” : only this directory (otherwise, it reads all included)

Mount iso file on linux

sudo mount -o loop <image>.iso /mnt/<folder>

If you mount another iso file to the same , it will replace the current one.

Extract a iso file: first, mount it like in 37 to folder named iso then copy all the contents in iso to some folder you want.

cp -r /mnt/iso <directory>

How to install matlab silently (only with command lines) on linux? (if below doesn’t work, you can cf here, my method is different from this one)

• Suppose that you have 2 dvd iso files which contains the installation of matlab (dvd1.iso and dvd2.iso)
• For the activation, you have libmwservices.so and license_standalone.lic
• First, you need to extract 2 dvd iso files to a common folder named install_matlab in /home/thi/
• Create a new folder to install matlab called matlabR in /home/thi/
• Extract all files in 2 iso files to folder install_matlab like the instruction 38

• Run below command line

  sudo /home/thi/matlab_install/install -agreeToLicense yes -mode silent -destinationFolder /home/thi/matlabR -fileInstallationKey xxxxx-xxxxx-xxxxx  -outputFile /home/matlab_install.log
  

• After the installation, copy file license_standalone.lic to /home/thi/matlabR/licenses/
• Copy file libmwservices.so to /home/thi/matlabR/bin/glnxa64/
• Try running matlab: /home/thi/matlabR/bin/matlab
• If you have an error like libXt.so.6: cannot open shared object file: No such file or directory, try to install sudo apt-get install libxt6.
• Make linux recognize your matlab command matlab like in the instruction 40.
• Finish.

Make linux recognize matlab command

• Suppose that you have installed matlab on /home/thi/matlabR

• You need to add above directory to the $PATH so that the system can recognize your matlab command

  export PATH=$PATH:/home/thi/matlabR/bin
  

• You can use echo $PATH to check if the path is located in it or not.

Sync files with mega right on terminal

• Install megatools: sudo apt-get install megatools
• Using megatools, cf the main website.

• Create a condig file which stores your login information (be careful, everyone can see your pass)

  sudo apt-get install vim # in case that you don't have vim on your system
  vim .megarc # create a file named .megarc
  

• vim opens and type

  [Login]
  Username = your@email
  Password = yourpassword
  

  If you have back slash in your password, you must escape it with another backslash

• Quit vim and save the file by pressing ESC and then :wq!
• Upload a file: megaput --path /Root/<folder> file
• See the list of file on remote: megals
• Upload a folder: megacopy --local <folder> --remote <folder>
• Download from link: megadl <mega-link>

• Download a single file: megaget <file>

  megaget /Root/Apps/matlab17b/R2017b_glnxa64_dvd2.iso
  

• Download from uploaded directory: megacopy --local <folder> --remote <folder-to-download> --download

Connect ssh to a virtual machine (the same network)

• Install openssh for both client and server machine

sudo apt-get install openssh-client
sudo apt-get install openssh-server

• On server machine, check ssh is running or not

ps -A | grep sshd
# return [number] ?  00:00:00 sshd then it works

Save a directory a $PATH of local profile.

sudo gedit ~/.profile
# copy and paste following line (should change the path)
export PATH=/home/thi/anaconda3/bin:$PATH
# save and close .profile and then apply following line to get instant update
source ~/.profile

Resize multiple photos (keep the ratio/scale) (more options):

# install
sudo apt-get install imagemagick

# resize but keep the ratio (save to jpg)
mogrify -resize 50% -format jpg *

# resize keep the extension
mogrify -resize 50% *

# with a specific size (save to jpg)
mogrify -resize 800x600 -format jpg *

# just the width (save to jpg)
mogrify -resize 800x -format jpg *

# only resize images bigger than 1000px width
mogrify -resize 1000x\> *

Shorten directory in terminal

• Temporarily, just enter PS1='\u:\W\$ ' en press enter.

• Permanently, open sudo gedit ~/.bashrc and find

  if [ "$color_prompt" = yes ]; then
    PS1='${debian_chroot:+($debian_chroot)}\[\033[01;32m\]\u@\h\[\033[00m\]:\[\033[01;34m\]\w\[\033[00m\]\$ '
  else
    PS1='${debian_chroot:+($debian_chroot)}\u@\h:\w\$ '
  fi
  

  Remove @\h and replace \w by \W so that it becomes,

  if [ "$color_prompt" = yes ]; then
    PS1='${debian_chroot:+($debian_chroot)}\[\033[01;32m\]\u\[\033[00m\]:\[\033[01;34m\]\W\[\033[00m\]\$ '
  else
    PS1='${debian_chroot:+($debian_chroot)}\u:\W\$ '
  fi
  

  Save, exit, close terminal and start another to see the result.

Check CPU & RAM info

# cpu
cat /proc/cpuinfo
# ram
cat /proc/meminfo

Add path to system

export PATH=/home/thi/bin:$PATH

But above command only works for current session, if you wanna add permanently, open ~/.profile and then paste above command into it and then save. Finally, do below command to make instantly worked!

source ~/.profile

Use ssh to get access to another computer in the same network (LAN)

1. Follow (a little bit) here.
2. On the remote machine
3. update and upgrade install
4. install openssh-server
5. open /etc/ssh/sshd_config and uncomment on Port 22 and lines starting with Hostkey...
6. start the network: sudo service ssh start
7. stop the network: sudo service ssh stop
8. check if the network is running or not? sudo service ssh status
9. Check the current ip: ifconfig: look on the inet
10. On the local machine
11. Install the same tool and use ssh username@remote-host

Look and kill an app process:

• Check the id: ps ax | grep teamviewer
• Kill: kill -9 <pid>

• F9: hide/show sidebar
• Menu on the top right > Add bookmarks
• Click on bookmark and rename it
• Ctrl + Shift + S to save (instead of Ctrl+S)

Remove PPA from ubuntu by terminal. For example, The repository ‘http://ppa.launchpad.net/b-eltzner/qpdfview/ubuntu artful Release’ does not have a Release file. Remove the file b-eltzner-qpdfview-ubuntu from directory /etc/apt/sources.list.d

sudo rm /etc/apt/sources.list.d/<file>

• Turn on the screen session: screen
• Detach the session (safely turn off computer while the session still on the remote): Ctrl+A and then D
• See the list of screen: screen -ls
• Go to some session: screen -r pts-0.phd-matlab
• Wanna kill some sesion:
  • First go to this session by screen -r
  • Then press Ctrl+A then K then y
• cf

• Don’t need to install any files if one needs to copy photos/videos from iphone to ubuntu, one can use gThumb to do this or just use file manager to copy.
• If one wants to copy files to iphone. Follow this one