Update prepend_text_to_file.sh

Author: djeada

src/prepend_text_to_file.sh

@@ -1,40 +1,65 @@
-#!/bin/bash
+#!/usr/bin/env bash
+set -euo pipefail
 
-# Function Name: prepend_text_to_file
-# Description: This function prepends provided text to the specified file.
-# If the file does not exist, it will be created, and the text will be written to it.
+# Function: prepend_text_to_file
+# Description: Prepend provided text to the specified file.
+#              If the file does not exist, it will be created.
 # Usage: prepend_text_to_file <file> <text>
-
 prepend_text_to_file() {
-
-    # Validate the number of arguments
-    if [ $# -ne 2 ]; then
-        echo "Error: Incorrect number of arguments."
-        echo "Usage: prependTextToFile <file> <text>"
+    # Require at least two arguments: a file and some text.
+    if [ "$#" -lt 2 ]; then
+        echo "Error: Incorrect number of arguments." >&2
+        echo "Usage: prepend_text_to_file <file> <text>" >&2
         return 1
     fi
 
     local file="$1"
-    local text="$2"
+    shift
+    # Combine all remaining arguments as the text to prepend.
+    local text="$*"
+
+    # If the file exists but is not a regular file, exit with error.
+    if [ -e "$file" ] && [ ! -f "$file" ]; then
+        echo "Error: '$file' exists but is not a regular file." >&2
+        return 1
+    fi
 
-    # Handle the case where the file does not exist by creating it
-    if [ ! -f "$file" ]; then
+    # If the file doesn't exist, create it.
+    if [ ! -e "$file" ]; then
         echo "Notice: File '$file' does not exist. Creating file..."
         touch "$file"
     fi
 
-    # Prepend the text to the file
-    { echo "$text"; cat "$file"; } > "temp" && mv "temp" "$file"
+    # Ensure the file is writable.
+    if [ ! -w "$file" ]; then
+        echo "Error: File '$file' is not writable." >&2
+        return 1
+    fi
+
+    # Create a secure temporary file.
+    local tmpfile
+    tmpfile=$(mktemp) || { echo "Error: Could not create temporary file." >&2; return 1; }
+    # Ensure the temporary file is removed on function exit.
+    trap 'rm -f "$tmpfile"' RETURN
+
+    # Prepend the text: write the new text first, then the existing file content.
+    { echo "$text"; cat "$file"; } > "$tmpfile"
+    mv "$tmpfile" "$file"
+    # Clear the temporary file trap (temporary file has been moved).
+    trap - RETURN
 
-    # Display log info in the console
+    # Log the action.
     echo "The following text was prepended to the file '$file':"
     echo "$text"
 }
 
+# Main function to call the prepend_text_to_file function.
 main() {
-    # Call the function
-    prepend_text_to_file "$1" "$2"
+    if [ "$#" -lt 2 ]; then
+        echo "Usage: $0 <file> <text>" >&2
+        exit 1
+    fi
+    prepend_text_to_file "$@"
 }
 
 main "$@"
-