How to Log Shell Script Output to File

Sometimes you may need to write the output of your shell script to a file, or redirect its output to a file. In this article, we will look at how to log shell script output to file.

How to Log Shell Script Output to File

Here are the steps to log shell script output to file.

1. Create empty shell script

Open terminal and run the following command to create an empty shell script.

$ sudo vi test.sh

2. Write Output to File

Add the following lines at the top of your shell script to write the output to a file /output.txt. Replace this path with the file path of your choice. Please note, you need to have write permission to the output file, otherwise the shell script will give an error.

#!/bin/bash
exec > /output.txt 2>&1

The exec command above will save shell script’s output to /output.txt file.

Then add your shell script’s code below as shown.

#!/bin/bash
exec > /output.txt 2>&1

echo "Start logging out from here to a file" 
echo "something happening"
echo "End logging out from here to a file"

Save and close the file.

3. Make shell script executable

Run the following command to make shell script executable.

$ sudo chmod +x test.sh

4. Test shell script

Run the shell script as shown.

$ ./test.sh

You will see the following output in terminal

Start logging out from here to a file
something happening
End logging out from here to a file

Now open the file /output.txt

$ cat /output.txt

You will see the following content of your file as, indicating that the output of your shell script has been written to it.

Start logging out from here to a file
something happening
End logging out from here to a file

How to Log Shell Script Output to File