Sort a.sort
The default sort in ascending order sorted by the first letter of each line of the file (number) of the ASCII table.
[root@lsl ~]# vi b.txt user1 user2 a b 1 10 6 11 5 22 c g
[root @ lsl ~] # sort -n b.txt // input information sorted by the numerical case A B C G user1 user2 . 1 . 5 . 6 10 . 11 22 is
Example: dividing the third column passwd directory, a sort p
sort -t ":" -k3 -n /etc/passwd
As can be seen from the drawing files sorted 012345
Example: Statistics repetition value and distinct values
vi c.txt // input values and a plurality of duplicate files in a non-duplicate test values A A B B B B B C G G G
[root @ LSL ~] # the Sort c.txt | uniq -c -d // duplicate values statistics
[root@lsl ~]# sort c.txt | uniq -c -u
Note: sort parameter
-n ordered according to numerical values
-f Ignore the case of letters
-t specify the delimiter (cut-d)
-k taken to specify the column
-u deduplication (consecutive identical values)
. B Programming principle:
1, Introduction to Programming
Objective: To allow hardware devices to achieve certain specified function of the human
How to recognize these hardware programming languages
Early language: basic
Assembly language
Limitations, each manufacturer has its own hardware devices can be recognized by the assembly language format
High-level languages: C ++ C # language C, the Java, Python, Go, perl, shell (humans tend to be able to read and write)
Compile: human able to identify programming language, translated into computer language that can be recognized
Depending on the programming mode is divided into:
1) compiled: compile once, all execution
2) Explanatory: Compile a row, to interpret a line, one line
Program instructions = data +
2, shell scripts Introduction
Advantages: the operating system command instructions
The python advantages: a large number of third-party modules, any function can be realized (the direction of automated operation and maintenance)
shell script the first sentence:
#! / Bin / bash // specify the following explanation of what language do
cat / etc / shells to see which shell procedures
Linux under each program has a user to start