bash guide for beginners

A small gift for beginners of bash-Linux general technology-Linux programming and kernel information. The following is a detailed description. Some common mistakes in bash programming come from abs-guide Note !!!! All the examples here are incorrect !!! ===== Variable usage ==== 1. Define the

　　At the beginning of the new year, the knowledge base of open source class is online. Early on, the Linux command Encyclopedia/bash Reference, Advanced Bash Scripting Programming Guide, is available in two series. Other materials are on the line.Among them, the Advanced Bash Scripting Programming

Advanced Bash Script Programming Guide-general Linux technology-Linux programming and kernel information. Read the following for details. Advanced Bash Script Programming Guide Main directory Part 1. Warm up 1. Why use shell programming? 2. Start with a Sha-Bang (Sha-Bang refers #!) 2.1. Call a script 2.2. Preliminar

color backgroundsa-53. The practice of Morse codea-54. BASE64 encoding/decodingA-55. Using sed in inserting text filesa-56. The Gronsfeld passwordAnn-57. Digital generatorsa-58. Basic knowledgeA-59. Test execution time for various commandsA-60. Associative arrays vs. legacy arrays (Execution time)C-1. The advent of counting lettersJ-1. Complete the script for usegetopt.shM-1. BASHRC file Sample.M-2. Bash_profile file.N-1. Viewdata.bat:DOS Batch processing filesN-2. Viewdata.sh:viewdata.bat Shel

It takes some time for BASH Shell to have a complete and in-depth understanding, but sometimes it is necessary to quickly master its basic usage and write simple programs to meet the needs of the project, then you can read the following article, otherwise you do not need to spend time on the following text. The first thing to clarify is that it is not necessary to make a detailed study of shell script programming. As pointed out in the title of this

File test operations-advanced bash Script Programming Guide /Span> 7.2 file testing operations----------------Returns true if...-E file exists-File a exists.This option has the same effect as-e, but it has been discarded and is not encouraged.-F file is a regular file (not a directory or a device file)-S file length is not 0-D files are directories.-File B is a block device (floppy disk, cdrom, etc)-The c f

Advanced Bash-scripting Guide (19th): maximum common divisor of two integers, bashscripting The example selected in this article is from the book "Advanced Bash-scripting Gudie", translated by Yang chunmin Huang Yi 1 #! /Bin/bash 2 # calculate the maximum common divisor of two integers 3 4 E_BADARGS = 65 5 6 # if the n

Advanced Bash-scripting Guide (17): use more to view gzip files, The example selected in this article is from the book "Advanced Bash-scripting Gudie", translated by Yang chunmin Huang Yi 1 #! /Bin/bash 2 # use more to view the gzip file 3 4 NOARGS = 65 5 NOTFOUND = 66 6 NOTGZIP = 67 7 8 if [$ #-eq 0] # [$ #-eq 0] has

Advanced Bash-scripting Guide (15th): Test broken link files (broken link ), The example selected in this article is from the book "Advanced Bash-scripting Gudie", translated by Yang chunmin Huang Yi 1 #/bin/bash 2 # use a pure shell script to find the bad link file 3 # What is broken link? For a symbolic link (soft li

Advanced Bash-scripting Guide (18): [[] and [] some special cases, bashscripting The example selected in this article is from the book "Advanced Bash-scripting Gudie", translated by Yang chunmin Huang Yi For example, [1-eq 1] [-n "'echo true 1> 2'"] # true. 1> 2 indicates to output the standard output to file descriptor 2 (standard error output: screen) 3 [2-

"$octal"]Ten Thenecho "$decimal equals $octal"Elseecho "$decimal isn't equal to $octal" # Equal to 017+ fi # doesn ' t evaluate within [single brackets]!if [["$decimal"-eq "$octal"]]Thenecho "$decimal equals $octal" # equals 017Elseecho "$decimal is not equal to $octal"FI # evaluates within [[double brackets]]!((...)) Arithmetic testIf the expression evaluates to 0, its exit status code is 1 or FalseIf the expression evaluates to non-0, its exit status code is 0 or TrueIts exit status and [...]

${file#*.} : Take out the first one. And the string to the left: file.txt${file##*.} : Take out the last one. And the string to the left: txt${file%/*}: Take off the last bar/its right string:/dir1/dir2/dir3${file%%/*}: Remove the first/its right string: (null value)${FILE%.*}: Take off the last one. And the string to the right:/dir1/dir2/dir3/my.file${FILE%%.*}: Take out the first one. And the string to the right:/dir1/dir2/dir3/myThis article is from the "Linux is belong to You" blog, make sur

output (stdout) of a previous command to the input (stdin) of the next oneThe pipe runs as a child shell, so you cannot modify the variables of the parent shell>| Force redirection|| Logical OR Background Run Job Logic and^ Line Head matchBack up files modified in the current directory in the last 24 hours1 #!/bin/bash23 # Backs up all files in current directory modified within last hours4 #+ in a "tarball" (tarred and gzipped file).56 backupfile=backup-$ (date +%m-%d-%y)7 # embeds date in back

Learning Guide for machine learning beginners (experience sharing)2013-09-21 14:47I computer research two, the professional direction of natural language processing, individuals interested in machine learning, so began to learn. So, this guy is a rookie ... It is because of their own is a rookie, so realize the hardships of self-study machine learning, so here to share a personal experience, hope to be help

　　Installed after the first step will definitely need to install an input method, and Sogou input method is the first choice for everyone, here we have to see what beginners should learn what basis it! Sogou Pinyin Input method is Sohu (or its Sogou search engine) introduced a phonetic Input method tool. It is different from the traditional method, using the search engine technology, is the second generation of input methods. As a result of the use o

Sogou Pinyin Input method is Sohu (or its Sogou search engine) introduced a phonetic Input method tool. It is different from the traditional method, using the search engine technology, is the second generation of input methods. As a result of the use of search engine technology, speed has a qualitative leap in the breadth of the word library, the accuracy of words, Sogou are far ahead of other input methods. But for beginners, sogou Input method or so

Beginners Guide to learn Dimension Reduction techniquesintroduction Brevity is the soul of wit This powerful quote by William Shakespeare applies well to techniques used in data Science Analytics as well. Intrigued? Allow me to prove it using a short story.In could ', we conducted a data Hackathon (a Data science competition) in DELHI-NCR, India.Register for Data Hackathon 3.0–the Battle of s

mysql| Beginners MySQL Beginners guide to use and introduction One, the connection MySQL. Format: mysql-h host address-u user name-P user Password 1, Example 1: Connect to MySQL on this machine. First in the Open DOS window, and then into the directory Mysqlbin, and then type the command mysql-uroot-p, enter after the prompt you to lose the password, if just ins

. Net Architecture Design Guide for beginners (1) the era of Hello World During the middle school, the school opened a computer class. At that time, the computer was a relatively rare thing. There were a dozen computers in the school, and they were specially located in a hall. The room was covered with thick carpets and covered with heavy curtains all day. The day before each class, we need to bathe in our

Data control WinForm.In addition, if you are WebForms application, open source Project Supermarket management system source code you can see,or download this directly (version older) Pdf.net_v4.6_opensource (new)Conclusion:sod is not only an ORM, it also has sql-map and DataControl, concrete can see the frame official website Http://www.pwmis.com/sqlmap, 9 years of historical achievements, solid and reliable.Thank you very much for seeing here, I believe you preliminary understanding of the bas