Linux cat command

In Linux, the “cat” command is used to concatenate and display the contents of one or multiple files. It can also be used to create new files and combine the contents of existing files. Here’s how to use the “cat” command:

1. Open a Terminal:
   Launch a terminal emulator on your Linux system.
2. Type the “cat” command:
   The basic syntax of the “cat” command is as follows:

   cat [options] [file(s)]

• The “[file(s)]” parameter represents the name(s) of the file(s) you want to display or concatenate. You can specify multiple file names separated by spaces.
• If you don’t provide any file name, “cat” will read input from the standard input (e.g., you can type directly into the terminal). For example, to display the contents of a file called “file.txt”, you can use the following command:

   cat file.txt

The “cat” command will output the contents of “file.txt” to the terminal.

3. Concatenating Files:
   “cat” can be used to concatenate the contents of multiple files and display them together. To concatenate multiple files, simply provide their names as parameters, separated by spaces. For example:

   cat file1.txt file2.txt

The “cat” command will concatenate the contents of “file1.txt” and “file2.txt” and display them in the terminal.

4. Creating and Combining Files:
   “cat” can also be used to create new files or combine the contents of existing files. To create a new file with “cat”, you can redirect the output to a new file using the “>” operator. For example:

   cat > newfile.txt

After executing this command, you can start typing the contents of the new file. Press Ctrl + D when you’re done to save the file.

To combine the contents of existing files and save them into a new file, you can use the “>” operator followed by the name of the new file. For example:

   cat file1.txt file2.txt > combined.txt

The “cat” command will concatenate the contents of “file1.txt” and “file2.txt” and save them into a new file called “combined.txt”.

5. Using Options:
   The “cat” command provides various options to modify its behavior. Some commonly used options include:

• “-n” (number lines): Display line numbers along with the contents of the file(s).
• “-E” (show line endings): Display a “$” character at the end of each line.
• “-s” (squeeze empty lines): Squeeze multiple consecutive empty lines into one.
• “-v” (show non-printable characters): Display non-printable characters using escape sequences. For example, to display the contents of a file with line numbers, you can use the following command:

   cat -n file.txt

6. Exiting the Command:
   Once you have obtained the desired results using the “cat” command, you can continue executing other commands or exit the terminal as needed.

The “cat” command is a versatile tool for displaying, concatenating, and combining the contents of files. It is particularly useful for quickly viewing the contents of files or merging them together.