Shell script development (3) - echo command

Shell's echo command is similar to PHP's echo command, both of which are used for string output. Command format:

echo string

1. • Display normal strings:

echo "It is a test"
#这里的双引号完全可以省略，以下命令与上面实例效果一致：
echo It is a test

2. • show escape characters

echo "\"It is a test\""
#同样，双引号也可以省略
echo \"It is a test\"

3. • display variable

The read command reads a line from standard input and assigns the value of each field of the input line to a shell variable

read name 
echo "$name It is a test"

The above code is saved as test.sh, name receives the variable of standard input, the result will be:

./test.sh

OK                     #标准输入
OK It is a test        #输出

4. Display newline

echo -e "OK! \n" # -e 开启转义
echo "It is a test"

Output result:

OK! It is a test

5. Display does not wrap

echo -e "OK! \c" # -e 开启转义 \c 不换行
echo "It is a test"

Output result:

OK! It is a test

6. The display results are directed to the file

echo "It is a test" > myfile

7. Output the string as it is, without escaping or taking variables (with single quotes)

echo '$name\"'

Output result:

$name\"

8. Display command execution results

echo `date`

Note: Backticks ` are used here , not single quotes ' .

The result will show the current date

Thu Jan 31 14:50:46 CST 2023