Bash Scripting

When writing, modifying, or debugging Bash shell scripts (e.g., build scripts, sync scripts, automation), follow these safety practices:

Sourcing vs Execution Safety (The `set -e` Trap)

If a script uses set -e, exit, or return and a user mistakenly runs it via source script.sh (or . script.sh) instead of executing it directly (./script.sh), it will instantly terminate their entire terminal session (because exit inside a sourced script exits the parent shell).

Always protect standalone operational scripts with a source-guard at the top:

BASH

#!/bin/bash

# Prevent the script from closing the user's terminal if they mistakenly source it
if [[ "${BASH_SOURCE[0]}" != "${0}" ]]; then
  echo "❌ Error: Do not source this script. Run it directly: ./script.sh or bash script.sh"
  return 1 2>/dev/null || exit 1
fi

# Exit on error
set -e

# ... rest of script

Directory Context

Never assume the script is executed from the directory it resides in. If your script interacts with files relative to itself, resolve its absolute directory first:

BASH

SCRIPT_DIR="$(cd "$(dirname "${BASH_SOURCE[0]}")" &> /dev/null && pwd)"

Sourcing vs Execution Safety (The set -e Trap)

Directory Context

Sourcing vs Execution Safety (The `set -e` Trap)