How to join PDF files in Mac on Terminal?

In Mac, you can use Preview to join multiple pdf files into a single pdf file. A more convenient way is to join/merge multiple pdf files from command line on Terminal. More recent Mac OS X versions already have Python script to merge multiple pdf files into a single pdf file. Here is how to […]






10 Easy Bash Shell Aliases

Aliases are great way to simplify the terminal experience. Basically an alias is a command line shortcut that allows one personalize the way one interact with Linux commands. The basic idea is to come with a simple version of your favorite command and add it to .bashrc file so that you can reuse the simple […]






How to Fold a Long Single Line Text to Multiple Lines (in Python and Linux)?

You might want to convert a really long string in a single line into multiple lines with specified width. For example, if you have string like 12345678912345678912345678912345678912345678910 and want to split the long text to multi-line text, where each line is of length w, like w=9 123456789 123456789 123456789 123456789 123456789 10 In the above […]






11 awesome ways to use find command in Linux to search files/directory

The find command is Linux is one of the most useful commands  for searching files and directories. At first the find command syntax might look a bit daunting, but once we get a hang of it, the find command is a great asset. How to print all files and directories in current directory? find . […]






Bash tip: Search through history using the up and down arrows

Ctrl-R is one of the most useful commands on the terminal and it allows to browse through command history and re-use it again. On bash shell there is a much simpler way to search through your command history on terminal. Basically you can start typing the initial letter and then use up and down arrow […]






How to Run a Shell Command from Python and Get The Output?

In Python, often you may want to execute linux command and get the output of the command as string variable. Naive way to do that is to execeute the linux command, save the output in file and parse the file. A better way to get the output from executing a linux command in Python is […]






How To Set PATH variable on Bash Shell?

Have a new executable file/program? Want to execute it just by typing the name of the program instead of full path where the program is located?  The best solution is to add the path to new executable to your list of all search paths. The idea is that every time one types a command the […]






How To Check If a File or Directory Exists Using Shell Script?

One of the common tasks in shell scripting in Linux/Mac OS, checking if a file or directory exists already and to create the file/directory if it does not exists. Here is how to check if a file or directory exists in Linux shell script. The basic syntax to check if a file exists is and […]






How to Find Where Linux/Mac OS X Commands Are Physically Located?

If you are a beginner it is a good thing to learn about the director/file structures of Linux/Mac OS. It is even better to start learning where the actually commands are located in your machine. You may roughly know that the commands are in some “bin” directory, but not the exact location. The command “type” […]






Understanding Variables in Shell Scripting

A number of beautiful and powerful programming languages, like Python, Ruby, and Perl are available for scripting needs. Even then you may find the old school unix shell scripting very useful tool to learn and use. For sure, shell scripts looks crazy and hard to read/understand. Once you get a hang of it, you might […]