Bash script or Python script file creation automation V1

#!/usr/bin/sh

help() {
    cat << EOF
Usage: make_new_cwd_script.sh [filename] [extension] [permissions] [editor]

The script creates a new shell or Python script file with the specified name and opens it in the chosen editor.

Arguments:
  filename    The name of the file to be created. Must contain only alphanumeric characters, underscores, and periods.
  extension   The file extension indicating the script type. Acceptable values are .sh for shell scripts and .py for Python scripts. Defaults to .sh if not provided.
  permissions The file permissions in octal format (e.g., 755). Defaults to 755 if not provided.
  editor      The text editor to open the file with. Acceptable values are: nano, vi, vim, gedit, vscode. Defaults to nano if not provided.

Examples:
  make_new_cwd_script.sh myscript .sh 755 nano    # Creates a shell script named myscript.sh with permissions 755 and opens it in nano.
  make_new_cwd_script.sh myscript .py 644 gedit   # Creates a Python script named myscript.py with permissions 644 and opens it in gedit.

Help Options:
  -?        Show the short help message.
  -h        Show the short help message.
  --help    Show the full help message.
  --man     Show the full help message.

Error Messages:
  "Error: Invalid filename format"  - The filename contains invalid characters. Only alphanumeric characters, underscores, and periods are allowed. (Exit Code: 1)
  "Error: [filename] exists"        - A file with the specified name already exists in the current directory. (Exit Code: 2)
  "Unknown editor specified. Please use nano, vi, vim, gedit, or vscode."  - The specified editor is not recognized. Only nano, vi, vim, gedit, and vscode are accepted. (Exit Code: 3)
EOF
}

# Display help if requested
if [[ "$1" == "-?" || "$1" == "-h" ]]; then
    help 0
    exit 0
elif [[ "$1" == "--help" || "$1" == "--man" ]]; then
    help 1
    exit 0
fi

# Ensure filename is provided
if [[ -z "$1" ]]; then
    echo "Error: Filename is required"
    exit 1
fi

# Check if the name contains only alphanumeric characters, underscores, and periods
if [[ ! "$1" =~ ^[[:alnum:]_.]+$ ]]; then
    echo "Error: Invalid filename format"
    exit 1
fi

# Store the filename by appending the appropriate extension based on the script type
name="$1"
extension="${2:-.sh}"  # Default to .sh if not specified
perm="${3:-755}"  # Default permissions to 755 if not specified
editor="${4:-nano}"  # Default editor to nano if not specified

# Determine the extension based on the desired script type
case "$extension" in
    .sh|.py) ;;
    *)
        echo "Error: Invalid extension. Use .sh or .py."
        exit 1
        ;;  # Exit if invalid extension is provided
esac

# Append the extension if it's not already present
if [[ ! "$name" =~ \.${extension#*.}$ ]]; then
    name="$name$extension"
fi

# Check if a file with the same name already exists
if [ -e "$name" ]; then
    echo "Error: $name exists"
    exit 2
fi

# Validate the editor before proceeding
case "$editor" in
    nano|vi|vim|gedit|vscode) ;;
    *)
        echo "Unknown editor specified. Please use nano, vi, vim, gedit, or vscode."
        exit 3
        ;;
esac

# Create the file with the specified name, including the shebang line
if [ "$extension" == ".sh" ]; then
    printf '%s\n\n' '#!/usr/bin/sh' > "$name"
else
    printf '%s\n\n' '#!/usr/bin/python3' > "$name"
fi

# Change ownership and permissions of the file
chmod "$perm" "$name"

# Open the file for editing using the specified text editor
case "$editor" in
    nano) nano "$name" ;;
    vi) vi "$name" ;;
    vim) vim "$name" ;;
    gedit) gedit "$name" & ;;
    vscode) code "$name" ;;
esac