Commands: Simple text-based terminal tools

There was a time, long before the ubiquitous windows management on our desktops and desktops, when people used commands to get things done from the computer. These commands were entered on the terminal. There were no beautiful interfaces involved like the menus or the buttons. To see the contents of the directory, they go to the terminal and enter the words ‘ls’ and they see a list of names of files and directories displayed on their terminal with no fancy figures. Similar for every action we now do on the computer, there was an associated command.

Command means to order somebody to do somethings. In the world of computers, there are a fixed number of commands that we give to the computer and the computer can understand these commands. Though there are many research works to make computer understand a large number of commands. But as of 2012, the computers can only understand a limited set of commands.

A command is a software. But normally the word ‘command’ corresponds to the software that run on the terminal. These commands take as input textual information from the user (like the name of a file or an image) and generates textual information as output.

Some commonly used commands in Linux
• ls (to list the contents of a directory)
• cd (change directory)
• pwd (prints current working directory)
• grep (to search for a pattern in a file)