Shell Learning 17 - Shell for Loops

Similar to other programming languages, Shell supports for loops.
The general format of a for loop is:

for variable in list
do
command1
command2
...
commandN
done

A list is a sequence of values ​​(numbers, strings, etc.), each value separated by a space. Each time through the loop, assign the next value in the list to the variable.
The in list is optional, and without it, the for loop uses the command-line positional arguments.
For example, to sequentially output the numbers in the current list:

for loop in 1 2 3 4 5
do
echo "The value is: $loop"
done

operation result:

The value is: 1
The value is: 2
The value is: 3
The value is: 4
The value is: 5

Sequentially output characters in a string:

for str in 'This is a string'
do
echo $str
done

operation result:

This is a string

Display files in the home directory starting with .bash:

#!/bin/bash
for FILE in $HOME/.bash*
do
echo $FILE
done

operation result:

/root/.bash_history
/root/.bash_logout
/root/.bash_profile
/root/.bashrc