echo hello

int pid = fork ();if (PID > 0) {printf ("parent:child=%d\n", PID);PID = Wait ();printf ("Child%d is done\n", PID);} else if (PID = = 0) {printf ("child:exiting\n");Exit ();} else {printf ("fork error\n");}Fork creates a new process that returns two

By using TR, you can easily implement many of the most basic features of SED. You can see TR as a (extremely) simplified variant of sed: it can replace another character with one character, or it can completely remove some characters. You can also

1.2.1 Echo's quote questionFor the use of ECHO, note that the special case of single and double quotes is the point. To print "Hello world!" As an example.Echo Hello world!Hello world!Echo ' Hello world! 'Hello world!Echo " Hello world! "

PHP syntax basics, PHP syntax 1.PHP Syntax Basics $a = 10; Variables can be modified during the run process $a = ten; $a =; $b = 5; Echo $a+$b; Const THE_VALUE = 100; Constants can only be assigned one time, otherwise they will

Tlcl-view the world echo in shell eyes View the world in shell eyes Echo-display a line of text When you enter a command, bash expands the input characters before executing the command. Expand path Echo * Shell expands * to the name of the file in

In a structured command, the most basic type is the If-then statement if Commandthen Commandfibash the Shell's if statement executes the IF line definition of the command, and if the exit status code of the command is 0, then the command in the then

Tlcl-view the world echo in shell eyes, tlcl-view echo View the world in shell eyes Echo-display a line of text When you enter a command, bash expands the input characters before executing the command. Expand path Echo * Shell expands * to the

Description of variables and parameters the name of a variable to be replaced is the place where the value of the variable is saved. the value of the referenced variable is called the replacement of the variable. $ this symbol is like a sign that

For linux: tr command usage, tr can be viewed as a simplified sed tool. tr is represented as: translate. The tr command is mainly used to convert strings in the following two replacement operations. The string conversion of the delete operation can

Shellshock analysis CVE-2014-6271 Some time ago, the shell-breaking vulnerabilities made various companies very busy. The vulnerabilities have been around for a while, and the analysis of the Internet has also been transferred. When they stop, it's

A lot of people are learning C + + language First, then learn shell script. If you have a little programming base, it's easy to understand the so-called order, selection, and loop. Order structure In fact, there is nothing to say, before the contact

One, automatically padded: [Tab] A lot of people should be able to do this by pressing the [TAB] key when entering commands, directories, or filenames. The system will help you fill in what you might want to enter, if more than one selection system

A simple small question fills in blank questions, and outputs helloworld. I have never done it before. There are many ways to narrow down the question. At present, I think there are 14 short answers. I wonder if you can make it simpler. if (_____) {&

Preface Quick edit shell command line The most common cause is that Nux beginners say that the most annoying thing is Linux/Unix command lines. If you are an impatient person, you can first try the comprehensive exercises at the end of the article

A simple little topic Fill in the blanks and output Hello world. Have not done before, have so narrow the meaning, the method is also many. Now think of the short answer there are 14, I do not know whether it can be more simple ha Guys, play. if (_

Previous section review: Use of AT command Job: Create a task 10 minutes after shutting down the machine At now+10 minutesAt>shutdownAt>In this section we proceed to the second command of the routine task management command:

A simple little topic Fill in the blanks and output Hello world. Have not done before, have so narrow the meaning, the method is also many. Now think of the short answer there are 14, I do not know whether it can be more simple ha Guys, play. if (_

1.1.1Arrayarrays are variable arrays, multiple variables are grouped together and accessed by the same name. A number is a contiguous number of separate memory spaces (elements), each of which corresponds to a variable. Array elements are referenced

Previous section review:1. Use of the AT command2. Job: Create a task 10 minutes after shutdownAt now+10 minutesAt>shutdownAt>In this section we proceed to the second command of the routine task management command: CronBefore using the command, see

CBC byte flip attack-101 Approach 0x00 translator's preface Topic articles in drops: using CBC bit reverse attack to bypass encrypted session tokens The origin is a question produced by candy. I can see that the author of the original article