Shell Basic usage

#!/bin/bash #使用哪个shell执行echo "Hello World" username= "Tom" echo $username #chmod +x./test.sh settings can perform file #for loop output for skill in Ada coffe Action Java; Do echo "I am good at ${skill}script" Done#for file in ' ls/etc '; Do#echo "This is Name" ${file} #done # read-only variable readonly usernameusername= "STEVN" echo $username; #充值变量unset username# Intercept string string= "Alibaba is a great company" Echo ${string:4:9}array_name= (value0 value1 value2 value3) #数组元素echo ${array_ NAME[1]} #全部元素echo ${array_name[@]} #数组长度echo ${#array_name [@]}echo ${#array_name [*]} #数组其中一个元素长度echo ${#array_name [3 ]} #参数传递echo "parameter value is:" Echo echo $ echo $# echo $* echo $$ echo $!  echo [email protected] echo $-echo $? #运算val = ' Expr 2 + 2 ' echo ' two sum as: $val ' echo ' expr 2-5 ' echo ' expr 2\*5 ' echo ' expr 2%5 ' echo ' Expr 2/5 ' a=2b=2if [$a = = $b]thenecho "a==b" Elseecho "a!=b" fi if [$a-eq $b]thenecho "1" Elseecho "2" Fiecho "This is a test file" >test1.lua# Current date echo ' Date ' #按照格式打印printf "%-10s%-8s%-4s\n" name sex weight kg printf "%-10s%-8s%-4.2f \ n "Guo Jing male 66.1234 printf "%-10s%-8s%-4.2f\n" Yang over male 48.6543 printf "%-10s%-8s%-4.2f\n" Guo Fu 47.9876 #test判断num1 =100num2=100if test $[NUM1]- EQ $[num2]then echo ' The numbers is equal! ' else echo ' The numbers is not equal! ' fi# file to determine if test-e./bashthen Echo ' The file already exists! ' else echo ' The file does not exists! ' fi# written as a line (for a terminal command prompt) if [$ (ps-ef | grep-c "SSH")-gt 1]; Then echo "true"; Fifor Loop in 1 2 3 4 5do echo "The value was: $loop" donefor str in ' This is a string ' do echo $strdoneint =1while ($i nt<=5) do echo $int let "int++" Done#echo ' press <CTRL-D> exit ' #echo-n ' Enter your favorite movie name: ' #while read film#d o# echo "Yes!    $FILM is a good movie "#donefunWithReturn () {echo" This function adds the two numbers you enter ... "echo" enters the first number: "Read Anum echo" Enter the second number: "    Read Anothernum echo "two numbers for $aNum and $anotherNum!" Return $ (($aNum + $anotherNum))}funwithreturnecho "The sum of the two numbers entered is $?!"    Funwithparam () {echo "the first parameter is $!"    echo "The second parameter is $!"    echo "The tenth parameter is $ A!" echo "The tenth Oneparameter is ${10}! "    echo "11th parameter is ${11}!"    echo "The total number of parameters is $#!" echo "Output all parameters as a string $*!"} Funwithparam 1 2 3 4 5 6 7 8 9 34 73# contains the file source filename or. Filenameecho "test= ' 1223333 '" >./test1.luasource./test1.luaecho $test

　　

Shell Basic usage