What is done Linux command?

The done command in Linux is used to notify the shell that a background task has completed. It is primarily used in shell scripts to mark the end of a background task.

done Syntax:

rsync [options] source destination

done Options:

Option	Description
-v	Verbose output showing the files being transferred
-r	Recursively transfer files and directories
-a	Archive mode; preserves permissions, timestamps, etc.
-z	Compress file data during transfer
-h	Output numbers in a human-readable format
-P	Shows progress during file transfer
-n	Perform a trial run with no changes made
-u	Update: skip files that are newer on the destination
-e	Specify the remote shell to use

Parameters:

Parameter	Description
source	The source file or directory to copy
destination	The destination where files will be copied to

done Command Usage Examples:

Marking a Task as Completed

done task1

Marks the task named “task1” as completed.

Marking Multiple Tasks as Done

done task2 task3 task4

Marks multiple tasks (“task2”, “task3”, and “task4”) as done in one command.

Using Regular Expressions

done task*

Uses a regular expression to mark all tasks starting with “task” as done.

Adding Notes to a Completed Task

done -l "task5: Completed with notes"

Marks the task “task5” as done and adds the note “Completed with notes”.

Repeating the Last Done Task

done -r

Repeats the action of marking the last task as done.

Tip

When using the done command in Linux, make sure to properly complete the related loop or function before executing the done command to avoid syntax errors.

How do I use done in Linux?

To use the done command in bash, execute the following command:

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

What is the purpose of done in Linux?

The done keyword marks the end of a script’s loop construct, such as a for loop or while loop.

while condition; do
    # Commands to execute
done

How to properly close a loop in bash using done?

To properly close a loop in bash using the done command, ensure that the corresponding loop structure is completed and that the done keyword is correctly placed to mark the end of the loop.

for file in *.txt; do
    echo "Processing file: $file"
done

Can the done command be used outside of loops in bash?

No, the done command is specifically used to mark the end of loop constructs in bash scripts. It is not used outside of loops.

for i in {1..3}; do
    if [ $i -eq 2 ]; then
        echo "Found number 2"
    fi
done

How does done work in a nested loop?

When using nested loops in bash, each inner loop must have its corresponding done keyword to properly mark the end of the loop construct.

for i in {1..3}; do
    for j in {a..c}; do
        echo "Combination: $i$j"
    done
done

Is it necessary to use done after a while loop in bash?

Yes, the done keyword is essential to mark the end of a while loop in bash. If omitted, it will result in a syntax error.

while read line; do
    echo "$line"
done < file.txt

How to handle errors related to the done command in bash scripts?

To handle errors related to the done command in bash scripts, carefully check for correct placement and matching with the corresponding loop structure, ensuring there are no missing or extra done keywords.

for (( i=1; i<=5; i++ )); do
    echo "Iteration: $i"
done

Applications of the done command

• Terminating a loop in a bash script
• Marking the end of a group of commands in a script
• Used in conjunction with the for, while, or until loop constructs