Cat command – display the file contents on the terminal device

Linux There are many commands in the system for viewing the contents of files , Each command has its own characteristics , Like this cat Commands are used to view plain text files with less content .cat This command is also easy to remember , because cat In English it is “ cat ” It means , Kitty is not to give you a petite 、 Lovely feeling ？

Be careful ： When the file content is large , The text content will flash quickly on the screen （ Scroll ）, Users often can't see the specific content displayed . Therefore, for long file contents, you can press Ctrl+S key , Stop rolling screen ; as well as Ctrl+Q Key to resume scrolling ; And press Ctrl+C（ interrupt ） Key can terminate the execution of the command . Or for large files , Just use more Order it ！

Grammar format ：cat [ Parameters ] [ file ]

Common parameters ：

-n	Display row number （ Blank lines are also numbered ）
-s	Display row number （ Multiple blank lines count as one number ）
-b	Display row number （ Blank lines are not numbered ）
-E	Show... At the end of each line $ Symbol
-T	take TAB Characters appear as ^I Symbol
-v	Use ^ and M- quote , except LFD and TAB outside
-e	Equivalent to ”-vE” Combine
-t	Equivalent to ”-vT” Combine
-A	Equivalent to -vET Combine
--help	Display help information
--version	Display version information

Reference examples

Check the contents of the file ：

[[email protected] ~]# cat filename.txt

Check the contents of the file , And display the number of rows ：

[[email protected] ~]# cat -n filename.txt

Check the contents of the file , And add the line number and output it to another file ：

[[email protected] ~]# cat -n linuxcool.log > linuxprobe.log 

Empty the contents of the file ：

[[email protected] ~]# cat /dev/null > /root/filename.txt

Continuously write file contents , meet EOF End and save ：

[[email protected] ~]# cat > filename.txt <<EOF
> Hello, World 
> Linux!
> EOF

Make a floppy disk device into a mirror file ：

[[email protected] ~]# cat /dev/fd0 > fdisk.iso