Linux Shell Scripting Tutorial Series (10) Shell for loop

This article is the tenth part of the Linux Shell Scripting Series . For more Linux Shell tutorials, please see: Linux Shell Scripting Series Tutorials

Basically any language has its own loop statement, and Shell is no exception. Following the previous article , today I will introduce the usage of Shell for loop.

 

Shell for loop syntax

The syntax of the shell for loop is shown below

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, the values ​​in the list are sequentially placed into the specified variables, and then the command area (between do and done) is repeated until all elements are exhausted.

 

Shell for loop example

Next, I will introduce the usage of Shell for loop by way of example.

for loop in one two tree four
do
    echo "I am : $loop"
done

 

Output result:

I am : one
I am : two
I am : tree
I am : four

 

The words of the string can be output sequentially, for example:

for str in I am justcode.ikeepstudying
do
    echo $str
done

 

Output result:

I
am
justcode.ikeepstudying

 

You can display files in the current directory, for example:

for file in ./*
do
    echo $file
done

 

Output result:

./a.sh
./automake
./automonitor
./crzk
./make
./shell_start
./sql
./submit

 

The Shell for loop command is relatively easy to master, so I will introduce it to you today. For more Shell tutorials, please see: Linux Shell Scripting Series Tutorials

 

Original: Linux Shell series of tutorials (ten) Shell for loop

This article is transferred from: Linux Shell Scripting Tutorial Series (10) Shell for loop