Shell echo command

Shell echo command

The echo instruction for the shell is similar to the echo instruction for PHP and is used for the output of strings. Command format:

echo string

You can use echo for more complex output format control.

1. Show normal strings:

  echo "It is a test"

The double quotes here can be omitted, and the following command is consistent with the above example:

  echo It is a test

2. Show escape characters

  echo "\"It is a test\""

The result will be:

  "It is a test"

Similarly, double quotes can be omitted

3. Show variables

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

  #!/bin/sh
  read name 
  echo "$name It is a test"

The above code is saved as .sh, name receives the variables entered by the standard, and the result will be:

[root@www ~]# sh test.sh
OK                     #标准输入
OK It is a test        #输出

4. Show line changes

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

Output:

OK!

It it a test

5. Show no line changes

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

Output:

OK! It is a test

6. Display the results directed to the file

  echo "It is a test" > myfile

7. Output string as is, do not escape or take variables (with single quotes)

  echo '$name\"'

Output:

  $name\"

8. Show the results of command execution

  echo `date`

Note: Inverse quotes are ` instead of single ' .

The results show the current date

  Sat Dec 9 14:41:48 CST 2017