Shell

Select Connection Query Brief:Union Union Query Second, about the internal connection Union Union Query Function: Merge 2 or more query results together Details: (table 1 Query results) Union (table 2 query results) Execution: The results of

$#, the number of arguments followed by the script runtime#! /bin/bashCase ' $# ' in 0) printf "Enter A number: " Read n= $REPLY ;; *) n=$1 ;;EsacX=$ (((1 + $n) * $n/2))echo "Tne value of 1 + 2 + 3....+ $n = $x"The

sudo uname--m View the number of operating system bitssudo uname--s display kernel name ssudo uname--r display kernel versionsudo uname--n display the network host namesudo uname--p display CPUUnder Ubuntu, text files are usually opened with the

By using the Read command, you can output or perform operations after entering content from the terminal1 #!/bin/bash2#Author: Blacksonny3#Copyright (c)4 #Script follows here: 5 6 Echo " How is old is you ? " 7 Read Age 8 Echo " " $ageThe above

The shell is a program written in C language.Several common Shell:bash, SH, csh, ksh, etc.Bash is the default standard shell for Linux and is fully compatible with SHSH is the default standard shell for UNIXAsh is the smallest resource-intensive

#/secondin/secondfirstshecho "Please enter the Numseconder"Read FirstRead Secondif test $first-eq $secondThen echo "The No.2″"Elif Test $first-GT $second//Determine if it is greater thanThen echo "The No.2″ >else echo "No.2″ FiExample 2. Find out if

ReferenceCase , If I want to output an asterisk (*), How do i use echo ?echo *This is certainly not possible , need to transfer the * , that is : Echo \*This leads to the concept of references . referenced by , is used to prevent Shell to interpret

#!/bin/bash#斐波那契数列#不要用递归, the depth is more than 30 old fire. functionfun_test(){if[ $ -lt 3]; Then Echo 1 return fisum1=1Sum2=1 LetCount= $-2sum=0 while[$count -GT 0]; Do Letcount-- LetSum=sum1+sum2 LetSum1=sum2 LetSum2=sum

Method One: Add debugging options when you run the script:"Usage" bash– option./shellscript.sh-e: If a command returns a non-0 exit status value (failed), exit.-N: You do not need to execute the script just to check the syntax structure and return

When it comes to learning about Linux and OpenStack, it's important to learn scripts well, whether it's a large-scale deployment or operation, and shell scripts are already standard.Here are just some basic notes for the Linux shell, which are noted

CTRL key related shortcut keys:Ctrl + A-jump to the start of the lineCtrl + B-move back a charCtrl + c-terminate the command//use the most?Ctrl + D-delete from under the cursorCtrl + E-jump to the end of the lineCtrl + f-move forward a charCtrl +

Logon shell and non-logon shell read file procedureLogin:/etc/profile→/etc/profile.d/*.sh ~/.bash_profileNon-login: ~/.BASH_PROFILE→~/.BASFRC→/ETC/BASHRC#soure. Bash_profile Manual Update/etc/profile valid environment variables for general

1) Judgment expressionIfTest (expression is true)IfTest! expression is FalseTest expression 1–a expression 22 expressions are trueTest expression 1–o Expression 22 expressions have a true2) Judging the stringTest–n string string is not zero in

This document is referenced from http://www.cnblogs.com/zhuyp1015/archive/2012/07/11/2586985.htmlAWK: useful Data processing toolsAwk is also a great data-processing tool! SED is often used for the processing of an entire row, and awk prefers to

#!/bin/bash### #定义screen的名字, the following installation will use screen this command screen_name= "LANMP" #根据 $UID to determine whether the user is root, must root to perform if [  $UID  != 0 ]; then    echo  "You must be root to

Spark version 1.3.1Scala version 2.11.6Reference official website http://spark.apache.org/docs/latest/mllib-clustering.htmlAfter running Spark-shell, first import the required modulesImport Org.apache.spark.mllib.clustering.KMeansImport

Shell script [operation expression, conditional control statement] #! /Bin/bash # The four expressions you deserve to add to your favorites. Val1 = 1val2 = 1val3 = 1val4 = 1val5 = 1val6 = 1val7 = 1let val1 ++ (val2 ++) val3 = $ ($ val3 + 1 )) val4 =

Shell Script Programming #! /Bin/bash # Fibonacci sequence # Do not use recursion. If the depth is greater than 30, it will get old. Function fun_test () {if [$1-lt 3]; then echo 1 return fi sum1 = 1 sum2 = 1 let count = $1-2 sum = 0 while [$ count-

Shell script [Operational expressions, conditional control statements], shell expressions #! /Bin/bash # The four expressions you deserve to add to your favorites. Val1 = 1val2 = 1val3 = 1val4 = 1val5 = 1val6 = 1val7 = 1let val1 ++ (val2 ++) val3 =

Solution for shell not displaying the user name path in CentOS In CentOS, shell-bash-4.1 $ solution to not display the user name path Problem description: Add a new user under CentOS. After logging in, the shell script information is as follows: