As a beginner user of Unix or Linux, people would frequently get confused about the use of different directories of the system. For example, there is a /bin directory under root(/), it is used to store binary files. However, there are /usr/bin and /usr/local/bin under /usr which are used for storing binary files as well. Some systems even have /opt/bin. What are the differences among them?Though there are articles explaining different directories in *nix such as Filesystem Hierarchy Standard, it's not clear why these directories are present and their history. Rob Landley filled part ...

diff is an important tool program in Unix. It is used to compare differences of two files, it is the foundation for code version control. If you type :$ diff <file_before_change> <file_after_change>diff will tell you what's the difference between these two files. The result may not be so easy to understand, so now I will show you how to understand diff.1. 3 formats of diffdiff has 3 formats due to historic reasons.normal diffcontext diffunified diff2. Demo filesFor easy demonstration, we create 2 demo files.The first one is f1, it has 7 lines of a in it.aaaaaaaThe second file is f2...

Below is the collection of Linux command line tips which I’ve found useful for Linux users. To get more information about the command mentioned below just open your terminal and type man <command>.Things a Linux user must learnLearn bash: No need to refer a lengthy bash guide or something else. Just read the complete man page of bash (man bash).Learn vim: You might be using Emacs or Eclipse for your work all the time but nothing can compete vim.Learn ssh: Learn the basics of passwordless authentication.Learn basics of bash job management: Using &, Ctrl-C, fg, bg, Ctrl-Z, jobs,...

Every process is initialized with three open file descriptors, stdin, stdout, and stderr. stdin is an abstraction for accepting input (from the keyboard or from pipes) and stdout is an abstraction for giving output (to a file, to a pipe, to a console).That's a very simplified explanation but true nonetheless. Those three file descriptors are collectively called 'The Standard Streams'.Where does stderr come from?It's fairly straightforward to understand why stdin and stdout exist, however stderr seems like the odd one out. Why do we need another stream for errors?This is a quote from Doug McIll...

A few that come to mind, some less known, some more:xargs or parallel: run things in parallel, with lots of optionssed and awk: more well-known but still super useful for processing text files, and faster than Python or Rubym4: simple macro processorscreen: powerful terminal multiplexing and session persistenceyes: print a string a lotcal: nice calendarenv: run a command (useful in scripts)look: find English words (or lines in a file) beginning with a stringcut and paste and join: data manipulationfmt: format text paragraphspr: format text into pages/columnsfold: wrap lines of textcolumn: form...