Linux CAT command
Uses of cat command.
cat(concatenate) is one of the most basic commands in Linux operation systems. every programmer should know about the cat command. It can be used for doing a lot of things as mentioned below.
1) Create a file
The command is:
$ cat > file1
output:-
A new file with the name file1 will be created. Now you can write in the new text file once you are finished writing in the file press ctrl + d to save and exit.
example:- $ cat > file1 I am Advin Suryavanshi. I am a student. I am pursuing my bachelor of technology in computer science. ctrl + d
2) To view a file
The command is:
$ cat file1
output:-
This command is used to see the content of the file with the name file1.
3) To view multiple files
The command is:
$ cat file1 file2
output:-
This command is used to see the content of the file with the name file1 and file2.
4) To view the contents of a file with line numbers.
The command is:
$ cat -n file1
output:-
It shows content with line numbers.
example: $ cat -n file1
1 I am Advin Suryavanshi.
2 I am a student.
3 I am pursuing my bachelor of technology in computer science.
5) To write in an already existing file.
The command is:
$cat >> file1
hello reader.
output:-
It Will append the text "hello reader." to the end of the file1.
so if we will now view the file using $ cat file1.
the output will be
I am Advin Suryavanshi. I am a student. I am pursuing my bachelor of technology in computer science. hello reader.
6) To display content in reverse order
The command is:
$ tac file1
output:-
hello reader.
I am pursuing my bachelor of technology in computer science.
I am a student.
I am Advin Suryavanshi.
7) To see the content of all text files in the folder.
The command is:
$ cat *.txt
output:-
It Will show the content of all text files present in the folder.
8) Copy the contents from one file to another.
The command is:
$ cat [source file] > [destination file]
output:-
content for the source file will get copied into the destination file.
example: $ cat file1 > file2
now, file2 will have the content of file1.
9) To append one file's content to the end of another.
The command is:
$ cat file1 >> file2
output:-
content of file1 is appended at the end of file2.
10) To suppress repeated empty lines
The command is:
$ cat -s file1
output:-
In case your file has a lot of repeated empty lines. This command will reduce it to a single empty line.
11) To merge multiple files into one
The command is:
$ cat "file1" "fille2" "file3" > "final_file"
output:-
The content of file1, file2, and file3 will be inserted into the final_file in the given order.
12) To highlight the end of every line.
The command is:
$ cat -E "file1"
output:-
end of every line will be highlighted.
There are some other uses of the cat command too. here I have mentioned the most common uses of the cat command.