Bourne Again Shell Bash Commands for Ip Addresses Network Interface

Welcome to our ultimate guide to the Linux Command Line. This tutorial will prove you some of the key Linux command line technologies and introduce you to the Bash scripting language.

What is Bash?

Fustigate (short for Bourne Again Crush) is a Unix beat out, and a control linguistic communication interpreter. A vanquish is only a macro processor that executes commands. It's the most widely used trounce packaged by default for most Linux distributions, and a successor for the Korn shell (ksh) and the C shell (csh).

Many things that can be done Linux operating organization can exist done via command line. Some examples are…

• Editing files
• Adjusting the volume of the operating system
• Fetching web pages from the internet
• Automating piece of work you do every day

You tin read more nigh fustigate here, via the GNU Documentation, and via the tldp guide.

Using bash on the command line (Linux, Bone X)

You tin start using bash on most Linux and Os 10 operating systems by opening up a concluding. Let'southward consider a uncomplicated hi globe example. Open up your final, and write the following line (everything after the $ sign):

                zach@marigold:~$ echo "Hello world!" Hello world!              

As you can see, we used the repeat command to print the string "Hello world!" to the final.

Writing a fustigate script

You lot tin can besides put all of your bash commands into a .sh file, and run them from the command line. Say you lot had a fustigate script with the following contents:

                #!/bin/fustigate repeat "Hi world!"              

It's worth noting that commencement line of the script starts with #!. It is a special directive which Unix treats differently.

Why did we use #!/bin/fustigate at the beginning of the script file?

That is because it is a convention to let the interactive shell know what kind of interpreter to run for the program that follows. The first line tells Unix that the file is to be executed past /bin/bash. This is the standard location of the Bourne crush on just about every Unix system. Adding #!/bin/bash as the first line of your script, tells the OS to invoke the specified crush to execute the commands that follow in the script. #! is ofttimes referred to as a "hash-blindside", "she-blindside" or "sha-bang". Though information technology is only executed if y'all run your script as an executable. For example, when y'all type ./scriptname.extension, it will wait at the top line to find out the interpreter, whereas, running the script as fustigate scriptname.sh, start line is ignored.

Then you lot could run the script similar so: For brand file executable yous should phone call this control under sudo chmod +x "filename".

                zach@marigold:~$ ./myBashScript.sh Hello world!              

The script only has two lines. The first indicates what interpreter to use to run the file (in this case, bash). The second line is the command nosotros want to use, echo, followed by what nosotros desire to impress which is "Hello World".

Sometimes the script won't be executed, and the to a higher place control will return an fault. It is due to the permissions set on the file. To avoid that apply:

                zach@marigold:~$ chmod u+x myBashScript.sh              

And so execute the script.

Linux Command Line: Bash True cat

True cat is one of the most frequently used commands in Unix operating systems.

Cat is used to read a file sequentially and print it to the standard output. The proper noun is derived from its office to con true cat enate files.

Usage

                true cat [options] [file_names]              

Most used options:

• -b, numer non-blank output lines
• -due north, number all output lines
• -due south, squeeze multiple next blank lines
• -v, display nonprinting characters, except for tabs and the end of line character

Instance

Impress in final the content of file.txt:

                cat file.txt              

Concatenate the content of the two files and display the result in final:

                true cat file1.txt file2.txt              

Linux Control Line: Bash cd

Change Directory to the path specified, for instance cd projects.

In that location are a few really helpful arguments to assistance this:

• . refers to the current directory, such as ./projects
• .. can be used to move up i folder, employ cd .., and tin can be combined to move up multiple levels ../../my_folder
• / is the root of your system to achieve cadre folders, such as system, users, etc.
• ~ is the domicile directory, usually the path /users/username. Motility dorsum to folders referenced relative to this path by including it at the start of your path, for case ~/projects.

Linux Command Line: Bash head

Head is used to print the offset 10 lines (past default) or any other amount specified of a file or files. Cat is used to read a file sequentially and impress it to the standard output.
ie prints out the entire contents of the entire file. - that is not always necessary, perhaps you lot just desire to bank check the contents of a file to meet if information technology is the correct one, or cheque that it is indeed not empty. The head command allows yous to view the first North lines of a file.

if more on file is chosen and so the first ten lines of each file is displayed, unless specific number of lines are specified. Choosing to brandish the file header is optional using the option below

Usage

                head [options] [file_name(s)]              

About used options:

• -northward North, prints out the first N lines of the file(s)
• -q, doesn't print out the file headers
• -5, always prints out the file headers

Example

                head file.txt              

Prints in terminal the first ten lines of file.txt (default)

                head -n 7 file.txt              

Prints in terminal the first seven lines of file.txt

                caput -q -due north v file1.txt file2.txt              

Impress in concluding the commencement 5 lines of file1.txt, followed past the first 5 lines of file2.txt

Linux Control Line: Bash ls

ls is a control on Unix-like operating systems to list contents of a directory, for example binder and file names.

Usage

                cat [options] [file_names]              

Most used options:

• -a, all files and folders, including ones that are subconscious and start with a .
• -l, Listing in long format
• -G, enable colorized output.

Example:

List files in freeCodeCamp/guide/

                ls                                                                ⚬ primary CODE_OF_CONDUCT.md bin                bundle.json       utils CONTRIBUTING.physician    gatsby-browser.js  plugins            yarn.lock LICENSE.md         gatsby-config.js   src README.md          gatsby-node.js     static assets             gatsby-ssr.js      translations              

Linux Command Line: Bash man

Homo, the abbreviation of homo ual, is a bash command used to brandish on-line reference manuals of the given control.

Human being displays the reletive man page (brusque for man ual page ) of the given control.

Usage

                human [options] [command]              

Most used options:

• -f, print a short description of the given command
• -a, display, in succession, all of the available intro transmission pages independent within the transmission

Case

Display the man page of ls:

                homo ls              

Linux Command Line: Bash mv

Moves files and folders.

                mv source target mv source ... directory              

The first argument is the file y'all want to move, and the 2d is the location to motion it to.

Commonly used options:

• -f to force motility them and overwrite files without checking with the user.
• -i to prompt confirmation before overwriting files.

That'south all. Go forth and apply Linux.

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Source: https://www.freecodecamp.org/news/linux-command-line-bash-tutorial/

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