Shell

-eq equals-ne Not equal to-GT Greater than-lt less than-le less than or equal to-ge greater than or equal to-Z Empty string= Two characters equal! = Two characters are not equal-N Non-empty stringStrings are commonly used to check user input,

1. Crontrab for Linux in the projectScheduled execution under Linux is mostly done using a custom plan in the crontab file, but it's not very complex, and it's basically remembered once and for all, and the key is to remember the/var/spool/cron

Scrapy Python MrzontPublished on August 29, 2015 Recommended1Recommended Collection theCollection3kBrowse 0. Basic Environment Description This article and the operating environment are implemented on the WIN8 (yes, I have

Classification ReferenceFile Status Test -B filename Returns True when filename exists and is a block file (returns 0) -C filename Returns True when filename exists and is a character file -D

Simple to use:Awk: Performs an operation on a single line of the file in solitude.Awk-f: ' {print $1,$4} ': Use ': ' to split the line and print the first fourth field of the line.Detailed Description:awk Command IntroductionThe most basic function

#！ /bin/bashTwo ways to run the shellChange Permissions chmod u+xSpecifying the interpreter at run timeShell variablesVariable typeaccessing variables$, ${}Read-only variablesReadOnlyDelete a variableUnset cancels a variable, but cannot cancel a

The shell determines the file type.-D file to determine whether the file exists, and whether it is a directory (the directory is true)-e file to determine whether the file exists (exists as true)-F file to determine whether the file exists , and

GrepIn the past, we used grep to find lines in a file that contained certain strings, such as finding a string in a header file that fits a pattern (pattern), such as finding all strings that conform to the [email protected] pattern (that is, the

echo [options] [Output CONTENT]-E: Escape character that supports backslash controlExample: Echo-e "Hell\bo" → Output as "helo"Echo-e "\x68\t\x65\t\x6c\n\x6c\t\x6f\t" → output hello (with format)Echo-e "\e[1;34mthis is a blue\e[0m" → output blue

function definition Format:[function][()]{ action; [returnint;] }Cases:#!/bin/bash Funwithreturn () { Span class= "PLN" > echo echo "Enter first number : " read anum echo " Enter a second number: " read anothernum echo " two numbers are $aNum

Text Processing tools:The Three musketeers of text processing on Linux:grep: Text Filter tool (mode: pattern);grep: Basic Regular expression,-e,-fEgrep: Extended Regular expression,-g,-fFgrep: Regular expressions are not supported,-e,-gSed:steam

SED commandText Processing Three musketeers:Grep,egrep,fgrep: Text FilterSed: Stream editor, in behavior unitsawk: Text formatting tool, Report Buildersed [OPTION] ... {Script-only-if-no-other-script} [File] ...Common options:-N: Do not print the

String manipulation${#string} The number of characters in the output sentence${string:position:length} output $position The length of the start of the character${string:position}[[email protected] scripts]# liuyifei=] i like sanpan i like luo 

Yes, this is a simple script, do not write do not know, write to find out how many shortcomings.The following script is mainly used to bulk add the user's script, originally very simple script, but added some judgment, to verify their own learning.1.

Guide At the beginning of learning Inux shell scripting, for its arithmetic and logical operations. It is estimated that many friends feel more difficult to accept. When using the special variable logical operator "[]", you must ensure that

If the expression contains special characters, the Shell will replace it. For example, using a variable in double quotes is a substitution, and an escape character is also a substitution.As an example:#!/bin/basha=10Echo-e "The universe is $a \

If you want to intercept a string, you can do it by manipulating the subscript or pointer in C + +, and in a shell script, there are several ways to do this if you want to specify a string for interception:The following examples are used:str=

(a) Conditions to determine if the meaning of-Z to-D[-A file] is true if file exists.[-B file] True if file exists and is a block special file.[-C file] True if file exists and is a special file of a word .　　[-D file] True if file exists and is a

Thank you for the 36,000 sectionCommon Shell Categories: BASH: is the GNU Bourne Again Shell, which is the default shell on the GNU operating system C Shell: The BSD version of Sun's shell Look at where the shell is on the

#case: ESAC statement: with switch. Case similar, is a multi-branch selection structure#case语句匹配一个值或一个模式 if the match succeeds in executing the corresponding command, if the match does not execute the * command successfully#;; Similar to break, the