Shell

First, what is the shellThe shell is both an executable program and a programming language. as an executing program, it interactively interprets and executes user-entered commands , and is a bridge between the user and the Unix/linux; as a

Basic steps:1. Switch to the warehouse directory Rpm_list_dir1 and RPM_LIST_DIR22. LS lists the RPM package files of the warehouse and redirects them to the output files Rpm_list_file1 and Rpm_list_file2 respectively.3. Output the comparison results

1, write script/root/bin/systeminfo.sh, display the current host system information, including host name, IPV4 address, operating system version, kernel version, CPU model, memory size, hard disk size.#!/bin/bash# author:huiping# version:1.0.1# date:

The file name of the shell itself $1~ $n Each parameter value added to the shell. $ $ is the 1th parameter, and the $ = is the 2nd parameter ... $$ the shell itself PID (ProcessID) $! PID of the Shell's last running background process $?

What are positional variablesCalls the arguments passed to the script through the command line in the script code.What are the positional variables$1,$2,...: Corresponding to the 1th and 2nd parameters, Shift [n] position $: The command itself $*:

Brief description of single quotes, double quotes, and unquoted Name Explain Single quotation marks What you see is what you get: Everything inside a single quote is output as it is, or what you see in single

ObjectiveWhat the hell is a shell? Before this, we should understand the issue of file permissionsBody Shell versionVarious versions: Bourne Shell (SH), C Shell (CSH), and Korn Shell (Ksh)And at present:The common and CentOS default

The difference between one, ' and $ ()The anti-quote itself escapes the \, retains its own meaning, and if we want to play a special meaning in the anti-quote, we must use 2 \ to represent it. in inverted quotation marks: \ \ = \$ () in: \ = \Note:

Shell Execution Script 650) this.width=650; "Width=" 799 "height=" 321 "title=" QQ picture 20160809205710.png "Style=" width:607px;height:229px;float : none; "alt=" Wkiom1ep0pkiz2v4aac1d9tdasu417.png "src=" http://s4.51cto.com/wyfs02/M02

From http://www.cnblogs.com/wang-li/p/5728461.htmlLinux ops shell script gadget, if you want to share this article, please indicate the source of the article, the following script is for reference only, if the error placed on the server, the

1. Condition testing: Test or [If the test result is true, the exit status of the command is 0, and if the test result is false, the exit status of the command is 0Operation Result:Test commands with and, or, not[ ! Expr]: Expr can be any of the

Condition testThe command test or [can test whether a condition is true, if the test result is real, the exit status of the command is 0, if the test result is false, the exit status of the command is 1 (note the exact opposite of the logical

the difference between the ' and $ ' ():In Bash, $ () and "(anti-quote) are used for command substitution.Command substitution is similar to variable substitution, which is used to reorganize the command line, complete the command line in quotation

IP independent IP in the specified time of the non-pass IPSquid Statistics method[Email protected] etc]# cut-d ""-f1/usr/local/squid/var/logs/access.log|sort|uniq|wc-l2823When you use awkawk ' {print '} ' |sort|uniq

Bash variables: User-defined variables, environment variables, positional parameter variables, predefined variablesUser-defined variables:#变量赋值等号两侧不能有空格#调用变量加 $ eg. Echo $x#变量的叠加: x= "$x" 456 or x=${x}789Set #查看变量Set-u #echo时看变量是否存在unset variable

Simple comprehension: Use many tools to simplify complex steps in a shell scriptFrame: Must have notes, written by others can understandBeginning: #! The/bin/bash means that the file is using bash syntaxTo use this method to run a shell script, if

1. Create an alias$ alias dms='cd oracle/middleware/user_projects/domains/7001_costctl/'pwd /home/weblogic/oracle/middleware/user_projects/domains/7001_costctlCreating an alias is only temporary, and once the alias for the terminal setting is turned

1. After installing Spark, enter spark in the bin directory: Bin/spark-shell scala> val textfile = Sc.textfile ("/users/admin/spark/ Spark-1.6.1-bin-hadoop2.6/readme.md ") scala> Textfile.flatmap (_.split (" ")). Filter (!_.isempty). Map ((_,1)).

ExplainRedirect: Is an action, an Operation action actionFile descriptors: Nouns, another representation of a file, Linux everything is file."Base redirection form" Input redirect Usage Rating: * *

The Shell's handling of the problem is simple, but most of the online search is done under Linux. As follows: Sed-i ' s/[match string []/[Replace string]/g ' [filename] And my system is MacOS, using this command has been unsuccessful, are