Bash Script Syntax

How it works

A script is a text file containing commands. A shebang selects an interpreter when the operating system directly launches an executable file; explicitly running bash file.sh selects Bash independently of that line. Save scripts with LF line endings. A syntax check reads the program without running it, but cannot prove that file paths, utility options or runtime data are valid.

Run the code

Reviewed with Git for Windows Bash 5.2.37. Open Git Bash, save the download with LF line endings in a separate learning folder, check it with bash -n lesson-name.sh, then run bash lesson-name.sh using the actual filename. Bash 4 or newer is required for the full course. Linux-only notes identify unavailable tools or POSIX behaviour. There is no Bash browser runner; Apache and MySQL are not required.

This complete example was executed in the stated local review environment.

Download complete source

Example

#!/usr/bin/env bash
set -u
set -o pipefail
export LC_ALL=C
message="Map export"
if [[ $message == "Map export" ]]; then
    printf "Script branch selected\n"
else
    exit 1
fi

Expected result

Script branch selected

Every downloadable listing includes a Bash shebang and shared lab settings. Run bash -n script-syntax.sh to check grammar, then bash script-syntax.sh to execute. The if statement has an explicit failure branch instead of relying on an uninspected default. No executable bit is needed when passing the file to bash.