Linux Tutorials

Imagine having to execute a long running process and waiting for it to finish, most likely you are connected via ssh and you can’t do anything else but waiting for that process to finish. When the process is taking too long your connection will time out and you will be kicked out. When that happens…

SSH stands for “Secure Shell”. It is a protocol used to securely connect to a remote server. ssh is secure in the sense that it transfers the data in encrypted form between the host and the client. It transfers inputs from the client to the host and relays back the output. ssh runs at TCP/IP […]

Prepend content to a file Use sed with -i option. You can also specify the line to which the content will prepend to. sed -i ” ‘1s/^/package home;/” Home.java Prepend content to multiple files Here I need to add a package to 200 java files. To do this manual would be tedios. for f […]

Grep Grep command stands for “global regular expression print”. grep command filters the content of a file which makes our search easy. grep {search-key-word} {filename} // search for word lisa in test.txt file grep ‘lisa’ test.txt grep -n The -n option display the line number grep -n ‘lisa’…

Zip Zip is a compression tool. Zip files have the .zip extension. zip is very useful when you are on a limited bandwidth and need to send a big file over the internet. zip {options} {zipFilename} {files…} zip zipfile.zip test.txt test1.txt unzip {zipFilename} unzip myfile.zip Gzip gzip command…

vi stands for visual editor and comes as one of default applications in every Linux/Unix system. The vi editor has two modes. Command Mode: In command mode, actions are taken on the file. The vi editor starts in command mode. Here, the typed words will act as commands in vi editor. To pass a…

A system administrator manages configuration, upkeep and reliable operations of computer operations. Sysadmin handles servers, has to manage system performance and security without exceeding the budget to meet users need. A system administrator only deals with terminal interface and hence it is…

Netstat Netstat stands for network statistics. Network sockets can either be connected or waiting for a connection. The connections use networking protocols like Transport Control Protocol (TCP) or User Datagram Protocol UDP. They use Internet Protocol addresses and network ports to establish…

su The su command allows you to run a shell as another user. su {username} su root useradd useradd commands you can add a user. useradd -m -d /home/<userName> -c “<userName>” <userName> useradd -m -d /home/lisa -c “lisa” lisa userdel To delete a user account userdel command is used. By using…

The “man” is a short term for manual page. In unix like operating systems such as linux, man is an interface to view the system’s reference manual. A user can request to display a man page by simply typing man followed by a space and then argument. Here its argument can be a command, utility […]

There are many commands which help to look at the contents of a file. Now we’ll look at some of the commands like head, tac, cat, less & more and strings. Head The ‘head’ command displays the starting content of a file. By default, it displays starting 10 lines of any file. head {filename} […]

In Linux system, a file doesn’t include only text files, images and compiled programs, partitions, hardware device drivers and directories. Linux consider everything as as file are also files. Create a text file touch test.txt // using vi vi tes.txt // using vim vim test.txt Update content of an…

A directory is a file which job is to store the file names and the related information of its content. All the files, whether ordinary, special, or directory, are contained in directories. Unix uses a hierarchical structure for organizing files and directories. This structure is often referred to…

Linux is being used in our everyday lives in almost every device. As a developer it’s very important that you understand the basic use of linux for your day to day work. Some of your daily tasks may not require command line interaction as GUI for development tools rises but the 20% of the time […]