How to Run a .sh File on Linux

To run a .sh file on Linux you first need to ensure it has execute permissions by using chmod +x filename.sh. After that, you can run the script in different ways: with ./filename.sh if it’s in the current directory, or by calling the interpreter directly with bash filename.sh or sh filename.sh. Make sure the script includes a shebang line (e.g., #!/bin/bash) to specify the interpreter. If you encounter issues, check permissions or run with bash -x for debugging. For advanced users, adding the script to your PATH lets you run it from anywhere.

To run a .sh file (a shell script) on Linux, follow these steps:

1. Make the Script Executable

By default, shell scripts lack execute permissions. Use chmod to add them:

chmod +x your_script.sh

2. Run the Script

Method 1: Specify the Path

./your_script.sh

• Note: The ./ tells Linux to look for the script in the current directory.
• If you get a Permission denied error, revisit Step 1.

Method 2: Use the Shell Interpreter

bash your_script.sh

or

sh your_script.sh

• Works even if the script lacks execute permissions.
• Explicitly specifies the interpreter (Bash/sh).

Method 3: Full Path

/path/to/your_script.sh

• Use if the script is in another directory (e.g., /home/user/scripts/).

3. Advanced Execution

Run in the Background

./your_script.sh &

• Adds & to detach the script from the terminal.

Log Output to a File

./your_script.sh > output.log 2>&1

• Redirects stdout and stderr to output.log.

Run as Root (if needed)

sudo ./your_script.sh

4. Verify the Shebang Line

Ensure the script starts with a shebang line (e.g., #!/bin/bash) to specify the interpreter:

#!/bin/bash
echo "Hello, World!"

• If missing, the script may fail or use the wrong shell.

Troubleshooting

Permission Denied

chmod +x your_script.sh  # Fix permissions

“Command Not Found”

• The script’s directory may not be in your PATH. Either:
• Use the full path (e.g., ./script.sh).
• Move the script to a directory in PATH (e.g., /usr/local/bin).

Windows Line Endings

If the script was created on Windows, convert line endings with:

sudo apt install dos2unix  # Install tool (Debian/Ubuntu)
dos2unix your_script.sh    # Convert CRLF to LF

Debugging

Add -x to trace execution:

bash -x your_script.sh

Example Workflow

1. Create a script:

   echo '#!/bin/bash
   echo "Today is $(date)"' > my_script.sh

2. Make it executable:

   chmod +x my_script.sh

3. Run it:

   ./my_script.sh

Output:

   Today is Wed Sep 20 10:00:00 UTC 2023

Key Notes

• Security: Never run untrusted scripts! Inspect the code first.
• Arguments: Pass arguments to scripts like ./script.sh arg1 arg2.
• Editing: Use nano, vim, or a GUI editor to modify scripts.

Summary Table