Ajouts CRC32 checksum

miscellaneous/crc32_checksum_manager.sh

@@ -0,0 +1,101 @@
+#!/bin/bash
+
+# This script manages CRC32 checksums for files and directories.
+# It can create a checksum file for specified files or directories and verify them later.
+#
+# Usage:
+# To create a checksum file for a file or directory:
+# ./crc32_checksum_manager.sh --create /path/to/file_or_directory [output_file.txt]
+# To verify checksums using a checksum file:
+# ./crc32_checksum_manager.sh --verify /path/to/checksums.txt
+# Use -h or --help for usage information.
+
+# Error Messages:
+# ERROR: INVALID_PATH: $path
+#   Indicates that the specified path is neither a file nor a directory.
+# ERROR: CHECKSUM_FILE_NOT_FOUND: $checksum_file
+#   Indicates that the specified checksum file does not exist.
+# ERROR: CHECKSUM_INVALID: $file
+#   Indicates that the calculated checksum for the file does not match the expected checksum.
+# ERROR: MISSING_ARGUMENT: [specific_message]
+#   Indicates that a required argument (file or directory or checksum file) is missing.
+# ERROR: INVALID_OPTION: $1
+#   Indicates that an invalid option was provided to the script.
+
+# Function to display a help message
+show_help() {
+    echo "Usage: $0 [OPTION] [FILE_OR_DIRECTORY] [OUTPUT_FILE]"
+    echo "Options:"
+    echo "  -c, --create   Create a CRC32 checksum file for the specified file or directory."
+    echo "                 Optionally specify an output file name for the checksums (default: checksums.txt)."
+    echo "  -v, --verify   Verify the CRC32 checksums of the specified files or directory."
+    echo "  -h, --help     Display this help message."
+}
+
+# Function to create a CRC32 checksum file
+create_checksum() {
+    local path="$1"                 # Path to the file or directory to create checksums for
+    local output_file="${2:-checksums.txt}"  # Name of the output file where checksums will be saved, defaulting to 'checksums.txt'
+
+    if [ -d "$path" ]; then            # Check if the path is a directory
+        # Find all files in the directory and calculate their CRC32 checksums
+        find "$path" -type f -exec sh -c 'crc32 "$1" | awk "{print \$1, \"$1\"}"' _ {} \; > "$output_file"
+    elif [ -f "$path" ]; then          # Check if the path is a file
+        # Calculate the CRC32 checksum for the file and save it to the output file
+        crc32 "$path" > "$output_file"
+    else                               # If the path is neither a file nor a directory
+        echo "ERROR: INVALID_PATH: $path"
+        exit 1
+    fi
+}
+
+# Function to verify CRC32 checksums
+verify_checksum() {
+    local checksum_file="$1"           # Path to the checksum file
+
+    if [ ! -f "$checksum_file" ]; then # Check if the checksum file exists
+        echo "ERROR: CHECKSUM_FILE_NOT_FOUND: $checksum_file"
+        exit 1
+    fi
+
+    # Read each line of the checksum file
+    while read -r line; do
+        checksum=$(echo "$line" | awk '{print $1}')    # Extract the checksum from the line
+        file=$(echo "$line" | awk '{print $2}')        # Extract the file path from the line
+        # Compare the calculated checksum with the stored checksum
+        if [ "$(crc32 "$file")" != "$checksum" ]; then
+            echo "ERROR: CHECKSUM_INVALID: $file"
+        fi
+    done < "$checksum_file"  # Redirect the checksum file to the while loop
+}
+
+# Check the script's arguments and execute the appropriate functions
+case "$1" in
+    -c|--create)
+        if [ -z "$2" ]; then                # Check if a file or directory was provided
+            echo "ERROR: MISSING_ARGUMENT: No file or directory specified."
+            show_help
+            exit 1
+        fi
+        
+        # Call the create_checksum function with the provided path and optionally a custom output file
+        create_checksum "$2" "$3"
+        ;;
+    -v|--verify)
+        if [ -z "$2" ]; then                # Check if a checksum file was provided
+            echo "ERROR: MISSING_ARGUMENT: No checksum file specified."
+            show_help
+            exit 1
+        fi
+        
+        verify_checksum "$2"                 # Call the verify_checksum function with the provided checksum file
+        ;;
+    -h|--help)
+        show_help                          # Display the help message
+        ;;
+    *)
+        echo "ERROR: INVALID_OPTION: $1"
+        show_help
+        exit 1
+        ;;
+esac