In Linux, opening a file in read-only mode can be useful to prevent accidental modifications to the file contents. Read-only mode allows you to view the contents of the file, but you cannot make any changes to it. In this guide, we will show you how to open a file in read-only mode using various Linux commands.
Option 1: Using the less command
The less command is a powerful utility for viewing file contents on Linux. To open a file in read-only mode using less, simply use the “-R” option:
less -R filename
This will open the file in read-only mode, and you can view the contents of the file without the ability to modify it. To exit the less command, press the “q” key.
Option 2: Using the cat command
The cat command is another popular command for viewing file contents on Linux. To open a file in read-only mode using cat, simply use the “-v” and “-E” options:
cat -vE filename
This will display the contents of the file in read-only mode. The “-v” option will display non-printable characters, and the “-E” option will display a “$” character at the end of each line.
Option 3: Using the view command
The view command is a read-only version of the vi editor. To open a file in read-only mode using view, simply use the “-R” option:
view -R filename
This will open the file in read-only mode, and you can view the contents of the file without the ability to modify it. To exit the view command, press the “q” key.
Option 4: Using the chmod command
You can also use the chmod command to set the file permissions to read-only mode. To set the file permissions to read-only, use the following command:
chmod 444 filename
This will set the file permissions to read-only mode, and you will not be able to modify the contents of the file. To revert the file permissions back to their original state, use the following command:
chmod 644 filename
Commands Mentioned:
- less – displays file contents in a paginated manner
- cat – displays file contents
- view – opens a file in read-only mode using the vi editor
- chmod – changes file permissions
Conclusion:
In this guide, we have shown you how to open a file in read-only mode using various Linux commands. Opening a file in read-only mode can be useful to prevent accidental modifications to the file contents. The less, cat, and view commands allow you to view the contents of a file in read-only mode, while the chmod command allows you to set the file permissions to read-only mode.