How to Run a Script in Linux

Run Bash and executable scripts correctly using an interpreter, execute permissions and a shebang.

Short answer

$ ./script.sh

If it is not executable, use `bash script.sh` or add execute permission with `chmod +x script.sh`.

Linux gives you two common ways to run a script: pass it to its interpreter, or execute it directly with a valid shebang and execute permission.

Step by step

$ bash script.sh

The file itself does not need execute permission when Bash reads it explicitly.

$ chmod +x script.sh

Adds execute permission without requiring world-write access.

$ ./script.sh

The ./ prefix explicitly names the file in the current directory. A valid shebang should identify the interpreter.

$ bash -x script.sh

Prints commands as Bash executes them.

Use `./script.sh`, not `script.sh`, unless its directory is intentionally on PATH.
Use LF line endings; CRLF can cause bad-interpreter errors.
Avoid chmod 777.

The current directory is normally not in PATH, so ./ explicitly names the local file.

No. Passing the file to Bash does not require the file itself to be executable.

The script may lack execute permission, a parent directory may block traversal, or the filesystem may use noexec.

The path resolves fine — the system simply will not let you do that with it.

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Concepts involved: File permissions

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Replace text in one file or across a whole project, safely.