How to write file linux

4 Ways to Create a Text File in Linux Terminal

In this Linux beginner series, you’ll learn various methods to create a text file in Linux terminal.

If you have used the desktop oriented operating system such as Windows, creating file is a piece of cake. You right click in the file explorer and you would find the option of creating new file.

Things won’t look the same when you are in a command line environment. There is no right click option here. So how do you create a file in Linux then? Let me show you that.

Create file in Linux command line

There are various ways of creating a new file in Linux terminal. I’ll show you the commands one by one. I am using Ubuntu here but creating files in Ubuntu terminal is the same as any other Linux distribution.

1. Create an empty file using touch command

One of the biggest usages of the touch command in Linux is to create a new empty file. The syntax is super simple.

If the file doesn’t exist already, it will create a new empty file. If a file with the same name exists already, it will update the timestamps of the file.

2. Create files using cat command

Another popular way of creating new file is by using the cat command in Linux. The cat command is mostly used for viewing the content of a file but you can use it to create new file as well.

You can write some new text at this time if you want but that’s not necessary. To save and exit, use Ctrl+D terminal shortcut.

If the file with that name already exists and you write new text in it using the cat command, the new lines will be appended at the end of the file.

3. Create new file using echo command

The main use of the echo command is to simply repeat (echo) what you type on the screen. But if you use the redirection with echo, you can create a new file.

To create a new empty file using echo you can use something like this:

The newly created filename.txt file will have the following text: This is a sample text. You can view the file in Linux using cat or other viewing commands.

You are not obliged to put a sample text with echo. You can create an (almost) empty file using the echo command like this:

This will create a new file with just one empty line. You can check the number of lines with wc command.

4. Create a new file using a text editor like Nano or Vim

The last method in this series is the use of a text editor. A terminal-based text editor such as Emacs, Vim or Nano can surely be used for creating a new file in Linux.

Before you use these text editors, you should make sure that you know the basics such as saving an existing from the editor. Unlike the GUI tools, using Ctrl+S in the terminal won’t save the file. It could, in fact, send your terminal into a seemingly frozen state from which you recover using Ctrl+Q.

Let’s say you are going to use Vim editor. Make sure that you are aware of the basic vim commands, and then open a new file with it like this:

What’s your favorite command?

So, I just shared 4 different ways of creating a file in Linux. Personally, I prefer using touch for creating empty file and Vim if I have to edit the file. On a related note, you may want to learn about the file command in Linux that is helpful in determining the actual type of the file.

Which command do you prefer here? Please share your views in the comment section below.

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Thoughts on Magento, PHP, Linux and open source

Linux system programming: Open file, read file and write file

This is my first article in what I’m hoping will be a series of articles on system programming for POSIX compliant operating systems with focus on Linux. Actually I’ve touched this topic a while ago when I wrote three articles about library programming on Linux (static libraries, dynamic libraries and dynamic libraries using POSIX API). In this series my goal is to go trough basics of Linux system programming from the easiest topics like open file, read file and file write to a bit more complicated things like Berkeley sockets network programming. So lets get started with environment setup and an example of program that copies source file into destination file using POSIX API system calls to demonstrate open(), read() and write() system calls on Linux operating system.

Configuring your environment

I’ll use my trustworthy Ubuntu Linux operating system but you can actually use any POSIX compliant operating system, the only difference will probably be that you will need to configure your environment differently. What we need to begin with Linux system programming is gcc compiler with related packages and POSIX related man pages. So here’s how to install this packages on Ubuntu based operating system:

Basically that’s all you need to create serious system tools for Linux operating system. Later we will probably need some more libraries but we will install them when necessary.

open(), read() and write() system calls

If you have named this code file sp_linux_copy.c and if you want to name executable file sp_linux_copy to compile this program you would probably use something like this:

Then if your source file is named source_file.txt and if you want to name the destination file destination_file.txt you would run this program like this:

Now lets go trough the code and explain tricky parts. First thing we must do is to include necessary header files. Man page of every system call tells you what header files you need to include to be able to use this system call. Second we will define constant we will use to define size of our buffer in bytes. Smaller buffer size will make our copy process longer but it will save memory. Next we open source and destination file descriptors, source with O_RDONLY to make it read only, destination with O_WRONLY | O_CREAT to make it writable and to create destination file with 0644 file system permission flags. In case of error we use perror() man 3 perror to print relatively user friendly error message.

Now we are ready to start copy process. We run read() and write() inside loop (because source file might be bigger than our buffer) to copy from one file into another. Important to notice is that write() is using number of bytes read from source file returned by read() so it would know how much to write into destination file. If number of bytes read (ret_in) and number of bytes written (ret_out) differ this indicates error so once again we use perror() to print out error description. At the end if all went well we do cleanup by closing both file descriptors and returning 0 (EXIT_SUCCESS) to indicate that program ended without errors.

That’s it for this introductory article on Linux system programming topic. In my next article I will show you few more examples on POSIX input/output and then move on to memory management related system calls.

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Thread: writing to a file from the command-line

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writing to a file from the command-line

I have created a file called myfile.txt. So could someone tell me how to write something into the file from the command-line please

Re: writing to a file from the command-line

Re: writing to a file from the command-line

$cat some text > myfile.txt

$ cat some text >> myfile.txt .. append to file

Re: writing to a file from the command-line

$cat some text > myfile.txt

$ cat some text >> myfile.txt .. append to file

echo «some text»>>myfile.txt
cat «somefile.txt>>myfile.txt»

If you use only a single more than symbol >, it will delete the file and write ONLY what you asked it to. a double >> adds it onto the end without deleting anything.

cat is for files (It reads the file and outputs it, i.e. cat file.txt gives back the contents of file.txt)
Echo is for plain text.

Re: writing to a file from the command-line

Re: writing to a file from the command-line

Shows just how much of a noob i am. So i shall start from the beginning.

I created a text file called myfile.txt by using: touch myfile.txt
I also created a directory by using: mkdir Mytext
I moved myfile.txt into the Mytext directory by using: mv myfile.txt

/Mytext
I typed ls to make sure that myfile was inside the Mytext directory

Now while i was still in the Mytext directory i typed:
cat «Up hill and over dale»>>myfile.txt (clicked on Enter)

And was rewarded with: No such file or diectory

Would someone please tell me where i am going wrong?

Re: writing to a file from the command-line

I used: echo «Up hill and over dale»>>myfile.txt (clicked on enter)
and the used: cat myfile.txt to view the contents

Thanks for the replies everyone

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How to write the output into the file in Linux

How do I save terminal output to a file?

A command can receive input from a file and send output to a file.

Writing the output into the file

The syntax is
command > filename
For example, send output of the ls command to file named foo.txt
$ ls > foo.txt
View foo.txt using the cat command:
$ cat foo.txt
Please note that when you type ‘ls > foo.txt’, shell redirects the output of the ls command to a file named foo.txt, replacing the existing contents of the file. In other words, the contents of the file will be overwritten.

Appending the output or data to the file

The syntax is
command >> filename
For example the following will append data:

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Verify it:
cat /tmp/data.txt

How to save the output of a command to a file in bash using tee command

The tee command read from standard input and write to standard output and files. The syntax is as follows for writing data into the file:
command | tee file.txt
Want to append data? Try
command | tee -a output.txt

Examples

Display output of the date command on screen and save to the file named /tmp/output.txt. If the output.txt already exists, it gets overwritten:
$ date | tee /tmp/output.txt
$ cat /tmp/output.txt
Same as above but append to the given files, do not overwrite file:
$ pwd | tee -a /tmp/test.txt
$ echo «Today is $(date)» | tee -a /tmp/test.txt
$ hostnamectl | tee -a /tmp/test.txt
$ cat /tmp/test.txt

The above commands will append the output to the end of the file, just like the shell >> operator as explained earlier.

I/O redirection summary for bash and POSIX shell

Shell operator	Description	Overwrite existing file?
command > output.txt	Save terminal output (standard output) to a file named output.txt	Yes
command >> output.txt	Append terminal output (standard output) to a file named output.txt	No
command	Takes standard input from output.txt file	N/A
command 0	Takes standard input from output.txt file	N/A
command 1> output.txt	Puts standard output to output.txt file	Yes
command 1>> output.txt	Appends standard output to output.txt	No
command 2> output.txt	Puts standard error to output.txt	Yes
command 2>> output.txt	Appends standard error to output.txt file	No
command &> output.txt	Puts both standard error and output to output.txt	Yes
command > output.txt 2>&1	<POSIX> Puts both standard error and output to file named output.txt	Yes
command &>> output.txt	Appends both standard error and output to file named output.txt	No
command >> output.txt 2>&1	<POSIX> Appends both standard error and output to file called output.txt	No
command | tee output.txt	Puts standard output to output.txt while displaying output on screen	Yes
command | tee -a output.txt	Appends standard output to output.txt while displaying output on screen	No
command |& tee output.txt	Puts both standard output and error to output.txt while displaying output on terminal	Yes
command 2>&1 | tee output.txt	<POSIX> Puts both standard output and error to file named output.txt while displaying output on terminal	Yes
command |& tee -a output.txt	Append both standard output and error to file called output.txt while displaying output on terminal	No
command 2>&1 | tee -a output.txt	<POSIX> Append both standard output and error to file named output.txt while displaying output on terminal	No

Conclusion

You learned how to write the output to the file in Linux or Unix-like system when using bash or POSIX shell. We have:

1. /dev/stdin (standard input) — File descriptor 0 is duplicated.
2. /dev/stdout (standard output) — File descriptor 1 is duplicated.
3. /dev/stderr (standard error) — File descriptor 2 is duplicated.

See I/O redirection documentation for more information. We can read bash man page as follows using the man command:
man bash

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How to open, create, edit, and view a file in Linux

One thing GNU/Linux does as well as any other operating system is give you the tools you need to create and edit text files. Ask ten Linux users to name their favorite text editor, and you might get ten different answers. On this page, we cover a few of the many text editors available for Linux.

GUI text editors

This section discusses text editing applications for the Linux windowing system, X Windows, more commonly known as X11 or X.

If you are coming from Microsoft Windows, you are no doubt familiar with the classic Windows text editor, Notepad. Linux offers many similar programs, including NEdit, gedit, and geany. Each of these programs are free software, and they each provide roughly the same functionality. It’s up to you to decide which one feels best and has the best interface for you. All three of these programs support syntax highlighting, which helps with editing source code or documents written in a markup language such as HTML or CSS.

NEdit

NEdit, which is short for the Nirvana Editor, is a straightforward text editor that is very similar to Notepad. It uses a Motif-style interface.

The NEdit homepage is located at https://sourceforge.net/projects/nedit/. If you are on a Debian or Ubuntu system, you can install NEdit with the following command:

For more information, see our NEdit information page.

Geany

Geany is a text editor that is a lot like Notepad++ for Windows. It provides a tabbed interface for working with multiple open files at once and has nifty features like displaying line numbers in the margin. It uses the GTK+ interface toolkit.

The Geany homepage is located at http://www.geany.org/. On Debian and Ubuntu systems, you can install Geany by running the command:

Gedit

Gedit is the default text editor of the GNOME desktop environment. It’s a great, text editor that can be used on about any Linux system.

The Gedit homepage is located at https://wiki.gnome.org/Apps/Gedit. On Debian and Ubuntu systems, Gedit can be installed by running the following command:

Terminal-based text editors

If you are working from the Linux command line interface and you need a text editor, you have many options. Here are some of the most popular:

pico started out as the editor built into the text-based e-mail program pine, and it was eventually packaged as a stand-alone program for editing text files. («pico» is a scientific prefix for very small things.)

The modern version of pine is called alpine, but pico is still called pico. You can find more information about how to use it in our pico command documentation.

On Debian and Ubuntu Linux systems, you can install pico using the command:

nano is the GNU version of pico and is essentially the same program under a different name.

On Debian and Ubuntu Linux systems, nano can be installed with the command:

vim, which stands for «vi improved,» is a text editor used by millions of computing professionals all over the world. Its controls are a little confusing at first, but once you get the hang of them, vim makes executing complex editing tasks fast and easy. For more information, see our in-depth vim guide.

On Debian and Ubuntu Linux systems, vim can be installed using the command:

emacs

emacs is a complex, highly customizable text editor with a built-in interpreter for the Lisp programming language. It is used religiously by some computer programmers, especially those who write computer programs in Lisp dialects such as Scheme. For more information, see our emacs information page.

On Debian and Ubuntu Linux systems, emacs can be installed using the command:

Redirecting command output into a text file

When at the Linux command line, you sometimes want to create or make changes to a text file without actually running a text editor. Here are some commands you might find useful.

Creating an empty file with the touch command

To create an empty file, it’s common to use the command touch. The touch command updates the atime and mtime attributes of a file as if the contents of the file had been changed — without actually changing anything. If you touch a file that doesn’t exist, the system creates the file without putting any data inside.

For instance, the command:

The above command creates a new, empty file called myfile.txt if that file does not already exist.

Redirecting text into a file

Sometimes you need to stick the output of a command into a file. To accomplish this quickly and easily, you can use the > symbol to redirect the output to a file.

For instance, the echo command is used to «echo» text as output. By default, this goes to the standard output — the screen. So the command:

The above command prints that text on your screen and return you to the command prompt. However, you can use > to redirect this output to a file. For instance:

The above command puts the text «Example text» into the file myfile.txt. If myfile.txt does not exist, it is created. If it already exists, its contents will be overwritten, destroying the previous contents and replacing them.

Be careful when redirecting output to a file using >. It will overwrite the previous contents of the file if it already exists. There is no undo for this operation, so make sure you want to completely replace the file’s contents before you run the command.

Here’s an example using another command:

The above command executes ls with the -l option, which gives a detailed list of files in the current directory. The > operator redirects the output to the file directory.txt, instead of printing it to the screen. If directory.txt does not exist, it is created first. If it already exists, its contents will be replaced.

Redirecting to the end of a file

The redirect operator >> is similar to >, but instead of overwriting the file contents, it appends the new data to the end of the file. For instance, the command:

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