Shell's text processing-echo

one echo command output text 1.1 displaying normal strings

echo [Options] string

option means that the command option, only-n, does not output a newline character at the end of the line.

If the text you want to output is made up of multiple lists, enclose it in double quotation marks.

Echo-n "What's your first name?" 1.2 Show escape characters

To use the echo command to support escape characters, use the-e option.

\b Backspace

Echo-e "This is a\b string" (output this is string)

\c suppress continuation of output text

Echo-e "Hello \c world." (Output Hello)

\ r return character

\ n line break

1.3 Display variables

The Echo statement prints the value of a variable in the program, and you can use {} to define the variable name.

Echo-n "Please input a name:"

Read name

#输出变量的值

echo "Hello, $name"

v1= "Sing"

V2= "Danc"

#错误的输出变量值的方法

echo "We are $v 1ing and we are $v 2ing."

(Correct echo "We are ${v1}ing, we are ${v2}ing.") 1.4 Show Command execution results

Echo can display the results of the execution of the shell command, using the anti-quote "' to bring the command.

echo ' command ' 1.5 echo command execution result redirection

Redirection is the standard output of a shell command that is redefined to a file. By default, the standard output device for the echo command is a monitor, and sometimes the information displayed by the echo command is saved to a disk file. Redirect is now necessary.

The redirected operator is > or >>, and in the case of the target file, the former overwrites the original contents of the destination file, which appends the data to the end of the original file.

#将要输出的信息写入文件, it will overwrite

echo "Hello,world." > Hello.txt

#将输出的信息追加到文件的结尾, will not overwrite

echo "Hello,chunxiao." >> hello.txt