for command in Linux with Examples

Introduction

The for command in linux used in shell scripting to iterate over a set of values or perform set of tasks repeatedly. The for loop allows users to automate operations efficiently which is easier to maintain.

Syntax:

for NAME [in WORDS ... ] ; do COMMANDS; done

Here NAME takes the value of each item in the list.

WORDS contains a set of values.

COMMANDS contains a set of actions to perform.

Example:

for i in 0 1 2 3 4 do echo "$i" done

Output

Options used with for loop :

Iterating over files in a directory :

for file in *; do echo "$file" done

Output

The above image kept for reference. There are so many rows for this output.

Iterating over a range of numbers :

for i in {1..5}; do echo "Number $i" done

Output :

Using command output :

for process in $(ps -e | awk '{print $1}'); do echo "Process ID: $process" done

Output :

The above image kept for reference. There are so many rows for this output.

Options:

• help for : It displays help information.
• 

  Conclusion

  The for command in linux is essential tool in shell scripting. Whether iterating over files, lists the for loop enhances productivity. Understanding its various forms and applications allow users to write more powerful scripts which can create robust solutions.