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This article mainly introduces "how to use the Linux read command". In the daily operation, I believe many people have doubts about how to use the Linux read command. The editor consulted all kinds of materials and sorted out simple and easy-to-use operation methods. I hope it will be helpful to answer the doubts about how to use the Linux read command. Next, please follow the editor to study!

Linux commonly used commands read commands to read the value of variables from the keyboard, usually used in shell scripts to interact with the user.

Read reads variable values from the keyboard

Add that this command can read the values of more than one variable at a time, and the variables and entered values need to be separated by spaces. After the read command, if no variable name is specified, the read data will be automatically assigned to the specific variable REPLY

Syntax read (option) (parameter) option-p: specifies the prompt when reading the value;-t: specifies the time to wait when reading the value (in seconds). Parameter variable: specifies the variable name of the read value.

The following list of examples shows the common ways to use the read command:

Read 1987name reads the input from standard input and assigns a value to the variable 1987name. Read first last reads input from standard input to the first space or enter, puts the first word entered in the variable first, and places the rest of the line's input in the variable last. Read reads a row from standard input and assigns a value to the specific variable REPLY. Read-an arrayname reads the word list into the array of arrayname. Read-p "text" print prompt (text), wait for input, and store input in REPLY. Read-r line allows input to include backslashes. Read-t 3 specifies a read wait time of 3 seconds. Read-n 2 var reads two characters from the input and stores the variable var without pressing enter to read. Read-d ":" var ends the input line with the delimiter ":". The read command example reads input from standard input and assigns a value to the variable 1987name.

# read 1987name # wait for the input to be read until enter indicates that the input is complete, and assign the input to the variable answer HelloWorld # console enter Hello # echo $1987name # print variable HelloWorld to wait for a set of inputs. Each word is separated by a space until the enter ends, and the words are assigned to the three read variables in turn.

# read one two three 1 2 3 # enter 1 2 3 in the console, separated by a space. # echo "one = $one, two = $two, three = $three" one = 1, two = 2, three = 3REPLY example

# read # waits for console input and assigns the result to a specific built-in variable REPLY. This is REPLY # enter the line in the console. # echo $REPLY # print out a specific built-in variable REPLY to confirm that it is assigned correctly. Example of This is REPLY-p options

# read-p "Enter your name:" # outputs a text prompt, waits for input, and assigns the result to REPLY. Enter you name: stephen # enter stephen # echo $REPLY stephen after the prompt text to wait for console input, and treat the input information as an array, assign it to the array variable friends, and separate each element of the array with a space.

# read-a friends Tim Tom Helen # echo "They are ${friends [0]}, ${friends [1]} and ${friends [2]}." They are Tim, Tom and Helen. Add an example that does not allow the password to be displayed when the terminal enters the password.

Method 1:

#! / bin/bash read-p "enter password:"-s pwd echo echo password read, is "$pwd" method 2:

#! / bin/bash stty-echo read-p "enter password:" pwd stty echo echo echo has been entered. Where the option-echo forbids sending the output to the terminal, while the option echo allows it to be sent.

Use the read command to read the variable value from the keyboard and assign the value to the specified variable, enter the following command:

After read v1 v3 # reads the variable value and executes the above instruction, two pieces of data are required to be typed, as follows:

After the Linux c + # input data is complete, you can use the echo command to output the specified variable value for view, enter the following command:

Echo $v1 $v3 # output variable value after executing the command to output the variable value, the data value entered by the user is displayed, as follows:

Linux c + # output variable value Note: when you use the echo command to output a variable value, you must add the symbol $before the variable name. Otherwise, echo will output the variable name directly.

At this point, the study of "how to use the Linux read command" is over. I hope to be able to solve your doubts. The collocation of theory and practice can better help you learn, go and try it! If you want to continue to learn more related knowledge, please continue to follow the website, the editor will continue to work hard to bring you more practical articles!

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