Change open files linux

How to edit a text file in my terminal

I’m using Linux mint and using the vi command to create text files, now that I created a text file and saved it. How do I get back into to edit the text file again?

6 Answers 6

it, will open up a text editor to edit your file.

Here, you can edit your file in the terminal window.

Open the file again using vi. and then press » i » or press insert key ,

and write the following command

Open the file again using vi. and then press the insert button to begin editing it.

could also run ‘vimtutor’ to learn how to use vi/vim. This of course assumes you have vim (vi’s big brother) if you don’t run ‘sudo apt-get install vim’

If you are still inside the vi editor, you might be in a different mode from the one you want. Hit ESC a couple of times (until it rings or flashes) and then «i» to enter INSERT mode or «a» to enter APPEND mode (they are the same, just start before or after current character).

If you are back at the command prompt, make sure you can locate the file, then navigate to that directory and perform the mentioned «vi helloWorld.txt». Once you are in the editor, you’ll need to check the vi reference to know how to perform the editions you want (you may want to google «vi reference» or «vi cheat sheet»).

Once the edition is done, hit ESC again, then type :wq to save your work or :q! to quit without saving.

For quick reference, here you have a text-based cheat sheet.

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Everything you Must Know About How to Edit File in Linux? [Linux Edit File]

Are you new to working with Linux OS? This post will teach you on how to edit file in Linux or how to edit file in Linux without VI.

List of content you will read in this article:

Linux system allows the users to make the required changes to the files. For this, many text editors are available for carrying out easy changes. Not only this, you can run various commands from the command-line interface for editing the files. In this article, we will discuss how to edit file in Linux on various text editors and other command-line commands for making the desired file changes.

How to edit files in Linux via Vi editor?

You can open the Vi editor in the command-line terminal if you want to change a file. Once the terminal is open, you can type of below command to open the file in the Vi editor.

If you provide the file name that exists already, then the Vi editor will open this file in editing mode for you. But if you provide a file name that does not exist, it will create a new file for you.

If you are working with the Vi editor, you must understand the VI Editor commands for seamless and efficient working. It will speed up the editing process by entering direct commands. Below are some Vi commands-

i – this command will allow you to Insert wherever your cursor is (goes into insert mode)

a – it will allow you to write just after the cursor (goes into insert mode)

A – it will allow you to write at the end of the line (goes into insert mode)

ESC – this will allow you to exit the insert mode

u – it will allow you to undo the last change

U – it will allow you to undo all changes to the entire line

o – it will allow you to open a new line (goes into insert mode)

dd – it will allow you to delete the specific line

3dd – it will allow you to delete 3 consecutive lines.

D – it will allow you to delete the contents of the line just after the cursor

C – it will allow you to delete the contents of a line just after the cursor and allow you to insert new text. You can press the ESC key if you want to end insertion mode.

dw – it will allow you to delete the specific word.

4dw – it will allow you to delete 4 consecutive words

cw – it will allow you to change the specific word

x – it will allow you to delete the specific character at the cursor

r – it will allow you to replace the specific character

R – it will allow you to overwrite the characters just from the cursor onward

s – it will allow you to substitute one character just under the cursor and then continue to insert

S – it will allow you to substitute the entire line and begin to insert just at the beginning of the line

~ – it will allow you to change the case of a specific character

To run the above commands, you need to be in “command mode.” Vi editor is case-sensitive, and each command has its meaning, so you must ensure that you enter the right command. You can also use a, A, or o to get into the insert mode.

If you want to move within the file using the Vi editor, you can use the following options.

k – it allows you to move the cursor up

j – it will allow you to move the cursor down

h – it will allow you to move the cursor left

l – it will allow you to move the cursor right

To run these commands, you must be in “command mode.” Also, you can use the arrow keys on the keyword to make these movements within the file.

After making the required changes to the file using the Vi editor, it’s time to save the changes and close the specific file. You can use the following shortcuts to do so.

1. Shift+zz – it will allow you to save the file and quit
2. :w – it will allow you to save the file but keep the file open
3. :q – it will allow you to quit the file without saving it
4. :wq – it will allow you to save the file and quit vim

Again, to make such changes, you need to be in “command mode.”

Linux Edit file with Nano editor

Apart from the Vi editor, you can use the Nano editor to make the desired changes to the file. You can do it by running a simple command-

It will open the nano UI that looks like the image below.

You can also provide the filename and the nano command to launch the editor directly with a file.

nano [filename]
nano test.txt

In the above image, you can see that the screen is divided into four parts.

1. First, the line at the top of the screen will show the version of the editor, opened file, and the editing status of the file.
2. Second is the main editing area, where you can see the contents of the opened file.
3. Third, the highlighted line at the bottom of the edit area where you can see the important messages.
4. Last, the two lines at the bottom display the helpful commands for beginners performing basic nano commands.

Below, we have mentioned some commonly used shortcuts you should be aware of.

1. You can use the navigation keys on the keyboard to navigate within the file text.
2. To delete the text, you can use the backspace key.
3. To save the changes made to the file, you can use the ctrl+o.

Once you try to save the changes, the editor will ask for confirmation, as shown below.

You can now select any option to save the changes in various OS formats. You can press Alt+d to enable the DOS format and Alt+m for the Mac format.

To save the changes, you can press enter.

You can use the ctrl+k and ctrl+u for cutting and pasting the lines of the text. You can also use the keyboard shortcuts for cutting and pasting individual words, but you need to select the specific word for which you need to perform the action. To select the text, you can press the Alt+A and then the arrow key to select the complete word.

Apart from this, you can even perform search operations. You can use the ctrl+w for performing a simple search while the ctrl+\ for searching and replacing the text.

How to edit a File with Emacs Command Line Editor?

Another useful text editor of Linux is Emacs which will help edit the files using the command-line interface. You can run the following command to get started with the file edit.

sudo apt-get install emacs

Also, you can run the following command along with the file name that will open the file directly into the Emacs editor.

In the above command, the “-nw” flag is used for launching the Emacs in the bash itself rather than opening in a separate window by default.

This command will open the test file in the Emacs UI, as shown below.

Emacs UI is divided into different parts.

1. First is the top menu on the screen, which is similar to any graphical application.
2. Second is the main edit area, where you can see the file’s content. You can see the highlighted bar below the edit area that will show file details like name, editing mode, and status.
3. Last, there is an area where you can see the inputted command and output.

Once you make the desired changes to the file, it is time to save those changes using ctrl+x followed by ctrl+s. You can see the changes in the last area, as shown below.

But if you want to discard the changes made to the file and quit the editor, you can press the ctrl+x followed by ctrl+c. The editor will confirm the input command as shown below.

To confirm, you need to press yes, and the editor will quit without saving any changes to the file. If you want to delete the text, you can use the delete or backspace key from the keyboard. If you want to use the shortcuts, then you can use the ctrl+k for deleting a complete line, alt+d for deleting a specific word, and alt+k for deleting a sentence.

If you want to undo the changes, you can use ctrl+x followed by ctrl+u. If you want to re-do the undo changes, you can press ctrl+g followed by ctrl+_. For forward-searching, you can use the ctrl+s; for reverse search, you can press ctrl+r.

For performing a replacement operation, you need to use the alt_shift+%. Then the editor will ask you for the word you want to replace. Enter the word then the editor will ask for the replacement confirmation. In the below screenshot, the user is replacing the word “This.»

To launch a replace operation, use the Alt+Shift+% keyboard shortcut. You’ll be asked for the word you want to replace. Enter it. Then the editor will ask you for a replacement. For example, the following screenshot shows emacs asking the user about the replacement for the word ‘This.’

You must provide the replacement text for “This” and press enter. For carrying out each replacement operation, the editor will ask for your permission first:

After you are asked for permission, press ‘ y’, and the specific word will be replaced.

Conclusion

To use these Linux editors, you need to have a better grip on their specific shortcuts. If you use shortcuts, then you can seamlessly edit the files. For this, you need to practice a lot and remember various shortcuts. You can choose any of the editors of your choice and start practicing for a smooth performance. This is all about how one can edit/modify files in Linux operating system. Also, we have listed different Linux edit file commands that will help you to accomplish your goal.

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How do I change the number of open files limit in Linux? [closed]

When running my application I sometimes get an error about too many files open . Running ulimit -a reports that the limit is 1024. How do I increase the limit above 1024? Edit ulimit -n 2048 results in a permission error.

I just went through this on Centos 7 (same on RHEL) and made a blog post covering it because I had so much trouble even with all these posts: coding-stream-of-consciousness.com/2018/12/21/…. Often along with open files, you need to increase nproc which actually resides in multiple settings files. and if you use systemd/systemctl that has its own separate settings. It’s kind of nuts.

4 Answers 4

You could always try doing a ulimit -n 2048 . This will only reset the limit for your current shell and the number you specify must not exceed the hard limit

Each operating system has a different hard limit setup in a configuration file. For instance, the hard open file limit on Solaris can be set on boot from /etc/system.

set rlim_fd_max = 166384 set rlim_fd_cur = 8192 

On OS X, this same data must be set in /etc/sysctl.conf.

kern.maxfilesperproc=166384 kern.maxfiles=8192 

Under Linux, these settings are often in /etc/security/limits.conf.

There are two kinds of limits:

• soft limits are simply the currently enforced limits
• hard limits mark the maximum value which cannot be exceeded by setting a soft limit

Soft limits could be set by any user while hard limits are changeable only by root. Limits are a property of a process. They are inherited when a child process is created so system-wide limits should be set during the system initialization in init scripts and user limits should be set during user login for example by using pam_limits.

There are often defaults set when the machine boots. So, even though you may reset your ulimit in an individual shell, you may find that it resets back to the previous value on reboot. You may want to grep your boot scripts for the existence ulimit commands if you want to change the default.

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