Save the file in linux

How to Save a File in Vi / Vim Editor in Linux

It is true that learning Vi/Vim – a well-known text editor in the Linux ecosystem, is not as easy as learning Nano or Emacs, as it requires a little effort which is worthwhile.

Many people are afraid of learning it, but seriously, for no important reasons. In this short article, intended for Vi/Vim text editor newbies, we’ll learn a few basic commands; how to save a file after writing or modifying its content.

In most of the today’s Linux distributions, Vi/Vim editor comes with pre-installed, if not install the full version of Vim (Debian systems provide vim-tiny with less features), simply run this command:

Note: To use it’s latest features, install Vim 8.0.

To open or create a file using Vim, run the following command, then press i to insert text into it (insert mode):

Press ‘i’ to Insert Mode in Vim Editor

Once you have modified a file, press [Esc] shift to the command mode and press :w and hit [Enter] as shown below.

Save File in Vim

To save the file and exit at the same time, you can use the ESC and 😡 key and hit [Enter] . Optionally, press [Esc] and type Shift + Z Z to save and exit the file.

Save and Exit File in Vim

To save the file content to a new file named newname, use :w newname or 😡 newname and hit [Enter] .

From here, you can now move over to learn common Vi/Vim tips and tricks, understand the different modes and so much more:

That’s it! In an upcoming article, we’ll show you how to exit Vim text editor with simple commands. Remember to drop your comments via the feedback form below.

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How to save file in Linux using cat command

Linux cat command syntax

The syntax is:
cat filename
cat file1 file2 file3
cat [options] filename
cat > filename
cat >> filename

Showing file contents

Displaying /etc/hosts file contents in your terminal

Want to redirect contents of file to another?

Execute the following command to copy the contents of input.txt to output.txt using the > operator :
cat input.txt > output.txt
Of course, you can send output of any command to file too:
ls > dirs.txt
cat dirs.
Finally, one can use the >> operator to append the contents of files or command output to files too:
cat foo.txt >> bar.txt
date >> bar.txt
cat bar.txt

How to save file using cat command in Linux

Let us see how to make or create a file using cat command. It is recommended that you use a cat command when you need to create tiny files as it easier using a text editor such as nano or vim.

Step 1 – Create a new file named todays.txt using cat

We are going to create a new file, use the cat command as follows:
cat > todays.txt
Press the ENTER key. Type data you want. For example:
This is a test
Today’s date is Feb/13/2003

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Step 2 – Press the CRTL + D to save the file.

Simply hit the CRTL + D to save the file created by the cat command. To display, enter:
cat todays.txt

Gif 01: Creating and saving small files with cat command

Step 3 – Creating, saving and appending data to files

Please note that if a file named todays.txt is already existed, it will be overwritten by the cat. Use the >> shell operator to append the data/text to an existing file named todays.txt as follows:
cat >> todays.txt

Other cat command examples

Let us see how to print line numbers:
cat -n

/bin/gif
Sample outputs:

To see non printing characters such as $ (end of line), tabs and others, run:
cat

/bin/is_mounted.sh
Sample outputs:

See cat command man page online here or type the following man command:
man cat

Conclusion

We learned how to use the cat command to display or create a new file on Linux.

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How to save terminal output to a file under Linux/Unix

H ow do I save the terminal output to a file when using BASH/KSH/CSH/TCSH under Linux, macOS, *BSD or Unix-like operating systems?

Yes, we can save command output by redirecting it to a file. The standard streams for input, output, and error are as follows (also known as file descriptors):

Tutorial details
Difficulty level	Easy
Root privileges	No
Requirements	Linux, macOS, or Unix
Est. reading time	3 minutes

1. stdin (numeric value 0) – Keyboard
2. stdout (numeric value 1) – Screen/display
3. stderr (numeric value 2) – Screen/display

• Redirect stdout/stderr to a file
• Redirect stdout to a stderr OR redirect stderr to a stdout
• To redirect stderr and stdout to a file
• We can redirect stderr and stdout to stdout too
• And finally you can redirect stderr and stdout to stderr

How to save terminal output to a file

By default, the command sends outputs to stdout and can be redirected to the file using the following syntax:
command > filename.txt
For example, save the date command output to a file named mydate.txt, run:
date > mydate.txt
To view file contains use the cat command:
cat mydate.txt

Feed data to our commands (input redirection)

We can read input from a file using the following simple syntax and the file must already exist:
command

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Append output to a file

If the filename.txt/mydate.txt (file) already exists, it will get overwritten. To append output, run:
command >> filename.txt
echo «——————» >> mydate.txt
ls -l /etc/resolv.conf >> mydate.txt
Verify it:
cat mydate.txt

Please note that the file such as mydate.txt is overwritten unless the bash noclobber option is set using the set command. For example, turn off noclobber option:
set -o noclobber
echo «some data» > mydata.txt
Sample outputs:

We can turn on noclobber option as follows:
set +o noclobber
echo «foo bar» > mydata.txt

How to redirect stderr to a file

The syntax is as follows:
command &> file.txt
command &>> file.txt
OR
command 2> file.txt
command 2>> file.txt
Above works with bash and other modern shell. For POSIX version try:
command >output.txt 2>&1
command >>output.txt 2>&1
In this example, send the find command errors to a file named err.log:
find / -iname «*.conf» &>err.log
## OR ##
find / -iname «*.conf» 2>err.log
## POSIX version ##
find . -iname «*.conf» >err.log 2>&1
Verify it:
cat err.log
Sample outputs:

How to suppress error messages

Use the following syntax:
command 2>&-
find . -iname «*.txt» 2>&-
We can also redirect error messages (stderr) to standard output (stdout), run:
command 2>&1
echo «foo» 2>&1
kill $target_pid 2>&1 > /dev/null

How to redirect both stdout and stderr to a file

The syntax is as follows to redirect both stdout and stderr to a file:
command 2>&1 | tee output.txt
For example:
find . -iname «*.txt» 2>&1 | tee cmd.log
cat cmd.log
To append text to end of file use the following syntx:
find . -iname «*.conf» 2>&1 | tee -a cmd.log
cat cmd.log

How to combine redirections

The following command example simply combines input and output redirection. The file resume.txt is checked for spelling mistakes, and the output is redirected to an error log file named err.log:
spell error.log

How to redirect screen output (stdout) and errors (stderr) to /dev/null

Try the following syntax
command > /dev/null 2>&1
/path/to/script.py > /dev/null 2>&1

Redirect both standard error and standard out messages to a log file

command > log.txt 2>&1
/path/to/my-appname.py > my-appname.log 2>&1

Conclusion

You learned how to save terminal output to a file when using Linux or Unix-like operating system with modern shell such as Bash or KSH including POSIX syntax. See bash docs here for more info or type the following man command:
man bash

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How To Save a File in Vi / Vim Text Editor

How to save a file in Vi / Vim editor in Linux

The procedure is as follows:

1. Open vim in Linux. For example, type: vim test.c
2. Write code or programe
3. Save file in vim by pressing ESC and ZZ
4. This will save and exit in vim or vi text editor running on Unix or Linux

Let us see some more examples.

Save a File in Vim Text Editor

The vi or vim is a text editor who has three modes: command mode, input mode, and ex mode. When starting, vim or vi begins in command mode. One can press Esc key to return to command mode and issue various commands. To create a new file, open a terminal and then type:
$ vi demo.txt

vi / vim always begins in command mode. You can press [Esc] key anytime to return to command mode. Press i to insert text. To save and exit from vi / vim, press [Esc] key and type ZZ:
ZZ
To see list of your saved file use the cat command. Run:
$ ls
$ cat demo.txt
To just save file and not to exit to shell prompt, press [Esc] key and type w
w

vi ex Mode File Saving Commands

To get into the ex mode, press [Esc] key and then : (the colon). For example, to exit from vi saving changes, press [Esc], : (colon) and type wq:
:wq

Fig.01: vi / vim write and quit command in action

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Common Vi / Vim File Savings Related Commands (ex mode)

You need to press [Esc] key followed by the colon (:) before typing the following commands:

Command	Description
q	Quit
q!	Quit without saving changes i.e. discard changes and quit file
r fileName	Read data from file called fileName
w	Save file and continue editing
wq	Write and quit (save and exit)
x	Same as wq command i.e. write and quit (save and exit)
w fileName	Write to file called fileName (save as)
w! fileName	Overwrite to file called fileName (save as forcefully)

See Vi editor command keys wiki page for more information.

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How to Save the Output of a Command to a File in Linux Terminal [Beginner’s Tip]

Last updated April 17, 2021 By Abhishek Prakash 3 Comments

When you run a command or script in the Linux terminal, it prints the output on the screen for your immediate viewing.

There will be times when you need to save the output to a file for future references. Now, you can surely copy and paste in Linux terminal but there are better ways to save the output of a shell script or command in Linux command line. Let me show them to you.

Method 1: Use redirection to save command output to file in Linux

You can use redirection in Linux for this purpose. With redirection operator, instead of showing the output on the screen, it goes to the provided file.

• The > redirects the command output to a file replacing any existing content on the file.
• The >> redirects adds the command output at the end of the existing content (if any) of the file.

Use the STDOUT redirection operator > for redirecting the output to a file like this:

If the file.txt doesn’t exist, it will be created automatically. If you use the > redirect again with the same file, the file content is replaced by the new output.

The example below demonstrates it better. It first saves the output of ls -l command. And then later, it replaces the content of the file with the output of ls *.c command.

If you don’t want to lose the content of the existing file while saving the output of a script or command, use the redirection operation in append mode with >>.

This example demonstrates it better:

Even here if the file doesn’t exist, it is created automatically.

Bonus Tip: Save Linux command output as well as error to a file

If your Linux command returns an error, it doesn’t get saved in the file. You can save both the command output and command error in the same file using 2>&1 like this:

command > file.txt 2>&1

Basically, 0 stands for standard input, 1 for standard output and 2 for standard error. Here, you are redirecting (>) standard error (2) to same address (&) as standard output (1).

Method 2: Use tee command to display the output and save it to a file as well

By the way, did you notice that when you send the command output to a file, you cannot see it anymore on the display? The tee command in Linux solves this problem for you.

Like a tee pipe that sends water stream into two directions, the tee command send the output to the display as well as to a file (or as input to another command). You can use it like this:

Again, the file will be created automatically, if it doesn’t exist already.

You may also use the tee command in append mode with option -a in this manner:

Let me demonstrate it with some easy to follow examples:

I have used simple Linux commands in my examples. But rest assured, you can use these methods to save the output of bash scripts as well.

Note: Avoid pipe pitfall while saving command output to file

You probably are familiar with pipe redirection. You may use it to combine Linux commands but you cannot pipe the output to a file. It will result in error that filename command not found:

This is because pipe redirects the output of one command to input of another command. And in this case, you give it a file name while it was expecting a command.

If you are new to Linux command line, I hope this quick tutorial added to your Linux knowledge a bit. I/O redirection is an essential concept that one should be aware of.

As always, questions and suggestions are always welcome.

Like what you read? Please share it with others.

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