Linux cat Command With Examples

cat (short for concatenate) command is one of the most frequently used commands in Linux. It is used to view the content of a file, create single or multiple files, copy content from one file to another and concatenate files.

Most Common Use of cat Command

  • Create a new file
  • Read file
  • Display file
  • Modify file
  • Concatenate file

Syntax used for cat command:- Cat Option Filename

1. Display Content of Single File

Syntax: cat filename

It will show the content of a given file.

cat file1.txt


linux cat command

2. Display Content of Single File Along With Line number

Syntax: cat -n filename

It will show the content of the file preceding with line number.

cat -n file1.txt

linux cat command cat -n

3. Create a New File

Syntax: cat > new_filename

It will create a new file of the given filename. While you use cat > new_filenameon terminal, it will wait for input from the user. After typing desired text, press CTRL+D for exit.

cat > file3.txt

linux cat command

4. Display Content of Multiple File

Syntax: cat file1_name file2_name

It will show the content of a given file.

cat file1.txt file2.txt

linux cat command

5. Display Content of Multiple File Along With Line number

Syntax: cat -n file1_name file2_name file3_name

It will show the content of the file preceding with line number.

cat -n file1.txt file2.txt file3.txt

linux cat command

6. Copy the Contents of One File to Another File

Syntax: cat file1_name file2_name

file1_name: It should be the source filename whose content will be copied.

file2_name: It should be the destination filename where content will be copied.

Note:- If file2_name is not a new file then the content of file2_name will be overwritten by the contents of the  file1_name.

Example:

cat file1.txt > file4.txt

cat command in Linux / ubuntu

7. Append the Content of One File to End of Another File

syntax: cat file1_name >> file2_name

Using this command content of file1 will be appended at the end of file2.

Example:

cat file1.txt >> file2.txt

cat command in Linux / ubuntu

8. Show $ at the End of Line

Syntax: cat -E filename

Use “-E” option to show $ at the end of each lines and spaces between lines.

Example:

cat -E file1.txt

cat command in Linux / ubuntu

9. Show file’s content in reverse order

Syntax: tac filename

To display the file’s content in reverse order by lines use tac command. (using tac command First line will show at last line and vice-versa, Top 2nd line will show at bottom 2nd line and vice-versa, …………)

Example:

tac file1.txt

cat taccommand in Linux / ubuntu