Basic Commands: Difference between revisions

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Use the <code>rm</code> (stands for remove) command to remove the given file, multiple files, or a group/type of files. By default, the <code>rm</code> command does not require user confirmation to delete a file, but you can enable user confirmation using the <code>-i</code> option.

*<code>-d</code> deletes the specified empty directory.

Use the <code>man</code> command to display the user manual of the [[Linux]] command. Almost all the Linux commands have man pages, which is a kind of documentation that is displayed on the terminal. The Linux commands manual page explains what a particular command does, syntax, and accepted arguments.

Type man followed by the command name to display the command user manual page.

Similarly, you can also use the –-help option to display the help pages of a particular command.

The <code>chmod</code> command is used to change the mode (permission) of a file. The basic permissions a file can have are <code>r</code>(read), <code>w</code>(write), and <code>x</code>(execute).

For example to give <code>file1.txt</code> owner and group read and write permissions and only read permission to all others, type:

You may use -R option to recursively set permissions for all files and directories in a given directory.

To make the file executable, type:

The <code>chown</code> command is used to change file and directory ownership in Linux.

To change both owner and group of file, type:

You may use <code>-R</code> option to recursively set ownership for all files and directories in a given directory.

<code>pwd</code> stands for present working directory. The pwd command prints the absolute path of the current directory on your Linux terminal. The present working directory is the directory in which you are currently working.

'''Output'''

In the example <code>/home/kagtain</code> is the current directory.

Use the <code>uname</code> (stands for UNIX name) command to display fundamental information about your [[Linux]] computer. By default, this command prints only the type of the operating system, such as Linux. You can use different options with this command to print other information about your computer such as OS, kernel version, machine name, network, and so on.

The output of uname -a command on my machine:

All system information including OS type, name, user name, kernel release, and hardware platform is displayed.

Use the <code>who</code> command to list currently logged-in users on your Linux computer. This command also supports few options to display specific information, such as:

The output of who command looks like this:

It shows 3 users with their logged in date and time.

Use the uptime command to display the current system time, the duration for which the system has been up, the number of logged-in users, and average load time for 1, 5, and 15-minute intervals. This Linux command retrieves information from the <code>/proc/uptime</code> file.

The output of uptime command from my system:

Use <code>hostname</code> command to display the Domain Name System (DNS) name and set the hostname or Network Information System (NIS) of your system.

Display host name and domain name, type:

Some distributions allow you to set hostname for your machine, type:

You can replace NEW_HOSTNAME with your actual machine name.

Use the <code>top</code> or <code>htop</code> commands to monitor the server’s processes or vital system resources in real-time. Both these commands are used for the same purpose, but their output is different. The default output displays information about top CPU-consuming processes along with RAM usage.

The command also displays system up time, load average, number of logged in users, memory, total tasks, and running tasks.

<code>Htop</code> is an improved version of the <code>top</code> command. It display colorful text and allows for output scrolling. Htop doesnt comes preinstalled on most Linux distros.

Use the <code>touch</code> command to create an empty file on your Linux computer, or to modify the timestamp of a file. The primary function of this command is to update file timestamps, but it is most commonly used to create a file. The touch command can update access and modification timestamps of the specified file, and create the file if it does not already exist.