Ubuntu command line check disk usage

To check hard disk usage on Ubuntu from a terminal (command line), issue the following command  in your terminal.

liping:~$ df -h

-h stands for human which makes it readable by us humans, otherwise the file size will be in bytes:)

After you issue the command, you would  see your disk usage similar to the info given below.

Filesystem            Size  Used Avail Use% Mounted on
/dev/sda7              68G   23G   43G  35% /
udev                   10M     0   10M   0% /dev
tmpfs                 800M  1.6M  798M   1% /run
tmpfs                 5.0M     0  5.0M   0% /run/lock
/dev/sda6             264G  173G   78G  69% /home
tmpfs                 3.2G  992K  3.2G   1% /tmp
.
.
.

For more commonly used Linux commands, check my other posts at here  and here .

[LaTeX] subfigures with captions

This post provides Latex code examples for how to generate sub-figures with and without captions.

  • Sub-figures with captions
\documentclass{article}
\usepackage{graphicx, caption, subcaption}
\begin{document}
  This article is about ....

\begin{figure}
 \begin{subfigure}{0.96\textwidth} 
     \includegraphics[width=\textwidth]{subfig1} 
     \caption{subfig 1 caption text here}
 \end{subfigure} 
 \centering  %note: this centering command applies to subfig1
 \hfill
 \begin{subfigure}{0.47\textwidth}
     \includegraphics[width=\textwidth]{subfig2}
     \caption{subfig 2 caption text here}
 \end{subfigure}
 \hfill
 \begin{subfigure}{0.47\textwidth}
     \includegraphics[width=\textwidth]{subfig3}
     \caption{subfig 3 caption text here}
 \end{subfigure}
 \caption{the overall fig caption text here}
 \label{fig:subfig_example} % Give a unique label
\end{figure}

\end{document}
  • Sub-figures without caption
\documentclass{article}
\usepackage{graphicx}
\begin{document}
  This article is about ....

%*For figures without sub-captions
\begin{figure}
    \includegraphics[width=0.96\textwidth]{subfig1}
    \centering 
    \hfill
    \includegraphics[width=.48\textwidth]{subfig2} 
    \hfill
    \includegraphics[width=.48\textwidth]{subfig3}
    % figure caption is below the figure
    \caption{figure caption text here}
 \label{fig:subfig_example2} % Give a unique label
 \end{figure}
 
\end{document}

Install DB Browser for SQLite on Ubuntu 16.04

This post introduces how to install DB Browser for SQLite on Ubuntu 16.04.

For Ubuntu and derivaties, @deepsidhu1313 provides a PPA with the latest release at here:

https://launchpad.net/~linuxgndu/+archive/ubuntu/sqlitebrowser

Step 1: Add the PPA shown above by issuing the following command in your terminal:

$ sudo add-apt-repository -y ppa:linuxgndu/sqlitebrowser

Step 2: Update the cache using:

$ sudo apt-get update

Step 3: Install the DB Browser for SQLite package by issuing the following command:

$ sudo apt-get install sqlitebrowser

 

Reference:

http://sqlitebrowser.org/

[LaTeX] Add appendices in an article

This post introduces how to add appendices to an article.

The command \appendix  is included in all basic class files, so you do not need to include any extra package to add appendix, unless the journal that you aim at has specific appendix style requirements.

\begin{document}

\section{Your section name here}
\section{Your section name here}

% Activate the appendix in the doc
% from here on sections are numerated with capital letters 
\appendix

\section{Appendix A title here}
\subsection{Appendix subsection title here}
\subsection{Appendix subsection  title here}

\section{Appendix B title here}

\end{document}

VPN setup on Ubuntu 16.04 (using Cisco AnyConnect client)

This post introduces how to setup VPN on Ubuntu  16.04 LTS using Cisco AnyConnect Client.

Step 1:  Download Cisco AnyConnect client.

Penn Stater can download at here.

Step 2: Extract the file(s) and install as root.

(1) extract the downloaded file;

(2) then cd to the extracted directory where it has an installation .sh file;

(3) then issue the following command to install Cisco AnyConnect Client:

$sudo ./AnyConnectInstall.sh 

# note your .sh file may have slight different name

Step 3:  Run the following command.

$ sudo apt-get install openconnect network-manager-openconnect-gnome

We need to issue this command to  show Cisco Compatible VPN in the list when we open network manager and add a new VPN.

Step 4:  Open Network Manager.

 

Step 5: Add a VPN in the Network Manager

Step6:  Choose Cisco AnyConnect Compatible VPN (openconnect) and click Create.

Step 7: Enter the following info

  • Connection name: Tech Services VPN [Note you can name this as you wish]
  • Gateway: vpn.its.psu.edu  [type in your vpn accordinly]

Click Save.

Step 8: Open Cisco Anyconnect client

Type your VPN address in the connect to textbox, and then enter your username and psw.

Then you are ready to go:)

 

References:

VPN, CISCO AnyConnect, Linux

Cisco VPN client on Ubuntu 16.04 LTS

 

 

 

Two ways to merge PDF files on Mac (GUI and command line)

This post introduces how to merge PDF files on Mac from GUI and from Terminal on Mac OS.

(For Ubuntu and Windows users, check out my post here for solutions.)

Method 1: GUI — using Preview  that comes with your Mac OS.

Check here for how to combine PDFs and reorder, rotate, and delete pages. If the page is not accessible, check the pdf I linked to in the references.

Method 2: From Terminal

We will introduce using gs command.

many people may already have gs package  installed and are already using gs.

TO check whether your Mac has gs installed,  in your terminal, issue the following command:

$ which gs

If you see something like this “/usr/local/bin/gs”, you OS has gs installed

If you see something like “… command not found”, you will need to install gs first.

You can use brew to install it.

$ brew install gs

If you do not have brew installed, check: Install Homebrew.

After you have gs installed,

in your terminal, cd to the directory where the pdf files you want to merge are located, and then issue the following command:

$ gs -q -dNOPAUSE -dBATCH -sDEVICE=pdfwrite -sOutputFile=merged.pdf source1.pdf source2.pdf source3.pdf

Then you will see a merged.pdf appear in the same folder where you source pdfs are.

Note: You may encounter these two errors in your terminal after your issue the pdf merge command I mentioned above, but be assured, the merge.pdf is correct. you can double check if you are worried about that:)

 

References:

Use Preview to combine PDFs on your Mac (pdf)

How can I combine multiple PDFs using the command line?

 

Read the first line of a file from terminal (on Ubuntu and Mac)

This post introduces how to read the first line of a file from terminal. It works on both Linux (Ubuntu) and Mac OS.

For getting top or bottom 10 files under a director from terminal (on Ubuntu and Mac), check here.

Note: you do not need to install anything, it is built-in on your Ubuntu/Mac OS.

Step 1: open a terminal 

Step 2: cd to the directory where your file (e.g., .txt file) is located 

Step 3: issue the following command

$ head -n 1 example.txt  
# this will read and print the first line of the file in the terminal

$ head -n 2 example.txt 
# this will read and print the first two lines of the file ... you got the idea...

***********************************************

Analogously, see the following command for displaying the last line of a file from terminal:

$ tail -n 1 example.txt # this will read and print the last line of the file in the terminal 

$ tail -n 2 example.txt # this will read and print the last two lines of the file ... you got the idea...

Get top or bottom 10 files under a director from terminal (on Ubuntu and Mac)

This post get top/bottom 10 from the sorted file names in current directory.

For reading the first line of a file from terminal (on Ubuntu and Mac), check here.

Note: you do not need to install anything, it is built-in on your Ubuntu/Mac OS.

Step 1: open a terminal 

Step 2: cd to the directory where your file (e.g., .txt file) is located 

Step 3: issue the following command accordingly

$ ls | head -10

# the pipe symbol (i.e., |) puts the output of the ls command as the input of the head command.

if you would like to get more information of the files, use the following instead:

$ ls -l | head -10

similarly,

if you would like to get the bottom 10 files in the current directory, issue the following command:

$ ls | tail -10

or for detailed information of the files, use

$ ls -l | tail -10

You guessed it, if you would like to get the top/bottom 20, just change the -10 to -20:)

simply, enough, right?

 

For more commonly used Linux commands, check my other posts at here  and here .

Word count in pdf using wc command (on Ubuntu and Mac)

This post introduces how to count the number of words in a pdf file using wc command. It works on both Linux (Ubuntu) and Mac OS.

Note: you do not need to install anything, it is built-in on your Ubuntu/Mac OS.

Step 1: open a terminal 

Step 2: cd to the directory where your pdf file is located 

Step 3: issue the following command

$ ps2ascii example.pdf | wc -w

Step 4: Then you should see the number of words in that example.pdf

 

P.S.   the wc command has several arguments, see below.

wc -l: print the number of lines in a file.

wc -w: print the number of words in a file.

wc -c: print the number of bytes in a file.

wc -m: print the number of characters from a file.

wc -L: print only the length of the longest line in a file.

 

 

 

[LaTeX] Optional parameters explained for fine tuning the placement of tables and figures in LaTeX

This post introduces the optional parameters to fine tune the placement of tables and figures in LaTeX.

If you are using LaTeX, you have seen figure examples like the following

\begin{figure}[ht]
...
\end{figure}

These are optional parameters to fine tune the placement of tables and figures, the term is Float placement specifiers (introduced in detail below). LaTeX will try to honor the placement with respect to the actual place, the top or bottom of the page, or a separate page of floats coming immediately after the present insertion point.

Float placement specifiers

To direct a float to be placed into one of these areas, a float placement specifier has to be provided as an optional argument to the float.

If no such optional argument is given then a default placement specifier is used, which depends on the float class. Each float in LaTeX belongs to a class. By default, LaTeX knows about two classes,figureand table. A float placement specifier can contain the following characters in any order and combination:

  • ! — indicates that some restrictions should be ignored 
  • h — indicates that the float is allowed to be placed inline (i.e., here)
  • t — indicates that the float is allowed to go into a top area
  • b — indicates that the float is allowed to go into a bottom area
  • p — indicates the the float is allowed to go on a float page or column area

The order in which these characters are stated does NOT influence how the algorithm tries to place the float (e.g., [ht] or [th] will make no difference)! This is one of the common misunderstandings, for instance when people think that bt means that the bottom area should be tried first. You may also force LaTeX to “insist” on these specifications by adding an exclamation mark (!) before the placement parameters, e.g. \begin{figure}[!htb].

However, if a letter is not present then the corresponding area will not be tried at all.

For more detailed intro about this topic, check out How to influence the position of float environments like figure and table in LaTeX?

 

References: