Head and tail are as simple as their name, which is used to display the beginning or end of a number of chunks of text, the head is used to display the beginning of the file to the standard output, and tail to see the end of the file.
1. Command format:
Head [parameters] ... [File] ...
2. Command function:
The head is used to display the beginning of the file to the standard output, and the default head command prints the first 10 lines of its corresponding file.
3. Command parameters:
-Q Hide file names
-V Show file name
-c< bytes > Display bytes
-n< rows > rows displayed
4. Usage examples:
Example 1: Display the first n rows of a file
Command:
Head-n 5 Log2014.log
Output:
[email protected] test]# cat Log2014.log
2014-01
2014-02
2014-03
2014-04
2014-05
2014-06
2014-07
2014-08
2014-09
2014-10
2014-11
2014-12
==============================
[Email protected] test]# head-n 5 Log2014.log
2014-01
2014-02
2014-03
2014-04
2014-05[[email protected] test]#
Example 2: Displaying the first n bytes of a file
Command:
Head-c Log2014.log
Output:
[Email protected] test]# head-c Log2014.log
2014-01
2014-02
2014
[Email protected] test]#
Example 3: The file's contents except the last N bytes
Command:
Head-c -32 Log2014.log
Output:
[Email protected] test]# head-c -32 log2014.log
2014-01
2014-02
2014-03
2014-04
2014-05
2014-06
2014-07
2014-08
2014-09
2014-10
2014-11
2014-12[[email protected] test]#
Example 4: Output file except the last n rows of the entire content
Command:
Head-n-6 Log2014.log
Output:
[Email protected] test]# Head-n-6 Log2014.log
2014-01
2014-02
2014-03
2014-04
2014-05
2014-06
2014-07[[email protected] test]#
One Linux command per day: Head command