add cncount and cndel commands

BUILD.BAT

@@ -18,6 +18,14 @@ ECHO Compiling cndump.exe...
 TCC -A -w -ml -I.\include -ebuild\cndump.exe src\cndump.c
 IF ERRORLEVEL 1 GOTO ERROR
 
+ECHO Compiling cncount.exe...
+TCC -A -w -ml -I.\include -ebuild\cncount.exe src\cncount.c
+IF ERRORLEVEL 1 GOTO ERROR
+
+ECHO Compiling cndel.exe...
+TCC -A -w -ml -I.\include -ebuild\cndel.exe src\cndel.c
+IF ERRORLEVEL 1 GOTO ERROR
+
 ECHO.
 ECHO Build successful!
 ECHO.

CMakeLists.txt

@@ -0,0 +1,26 @@
+cmake_minimum_required(VERSION 4.1)
+project(cnotes C)
+
+# Force strict C90/ANSI compliance
+set(CMAKE_C_STANDARD 90)
+set(CMAKE_C_STANDARD_REQUIRED ON)
+set(CMAKE_C_EXTENSIONS OFF)
+
+# Strict warning flags to match Makefile
+set(CMAKE_C_FLAGS "${CMAKE_C_FLAGS} -ansi -Wpedantic -Wall -Wextra")
+
+include_directories(include)
+
+# Platform-specific definitions for Unix (IDE/static analysis support)
+# These match the defaults in platform.h for non-Windows/non-DOS builds
+add_compile_definitions(
+    PATH_SEP_STR="/"
+    HOME_ENV="HOME"
+    CNOTES_PATH_ENV="CNOTES_PATH"
+)
+
+# Separate executables
+add_executable(cnadd src/cnadd.c)
+add_executable(cndump src/cndump.c)
+add_executable(cncount src/cncount.c)
+add_executable(cndel src/cndel.c)

MAKEFILE.TC

@@ -23,7 +23,7 @@ BUILDDIR = build
 .c.obj:
 	$(CC) $(CFLAGS) -c -o$*.obj $<
 
-all: $(BUILDDIR) $(BUILDDIR)\cnadd.exe $(BUILDDIR)\cndump.exe
+all: $(BUILDDIR) $(BUILDDIR)\cnadd.exe $(BUILDDIR)\cndump.exe $(BUILDDIR)\cncount.exe $(BUILDDIR)\cndel.exe
 
 $(BUILDDIR):
 	if not exist $(BUILDDIR) mkdir $(BUILDDIR)
@@ -34,6 +34,12 @@ $(BUILDDIR)\cnadd.exe: $(SRCDIR)\cnadd.c $(INCDIR)\platform.h $(INCDIR)\config.h
 $(BUILDDIR)\cndump.exe: $(SRCDIR)\cndump.c $(INCDIR)\platform.h $(INCDIR)\config.h
 	$(CC) $(CFLAGS) -e$(BUILDDIR)\cndump.exe $(SRCDIR)\cndump.c
 
+$(BUILDDIR)\cncount.exe: $(SRCDIR)\cncount.c $(INCDIR)\platform.h $(INCDIR)\config.h
+	$(CC) $(CFLAGS) -e$(BUILDDIR)\cncount.exe $(SRCDIR)\cncount.c
+
+$(BUILDDIR)\cndel.exe: $(SRCDIR)\cndel.c $(INCDIR)\platform.h $(INCDIR)\config.h
+	$(CC) $(CFLAGS) -e$(BUILDDIR)\cndel.exe $(SRCDIR)\cndel.c
+
 clean:
 	if exist $(BUILDDIR)\*.exe del $(BUILDDIR)\*.exe
 	if exist $(BUILDDIR)\*.obj del $(BUILDDIR)\*.obj

Makefile

@@ -9,10 +9,10 @@ SRCDIR = src
 INCDIR = include
 BUILDDIR = build
 
-SOURCES = $(SRCDIR)/cnadd.c $(SRCDIR)/cndump.c
+SOURCES = $(SRCDIR)/cnadd.c $(SRCDIR)/cndump.c $(SRCDIR)/cncount.c $(SRCDIR)/cndel.c
 HEADERS = $(INCDIR)/platform.h $(INCDIR)/config.h
 
-TARGETS = $(BUILDDIR)/cnadd $(BUILDDIR)/cndump
+TARGETS = $(BUILDDIR)/cnadd $(BUILDDIR)/cndump $(BUILDDIR)/cncount $(BUILDDIR)/cndel
 
 .PHONY: all clean install uninstall
 
@@ -27,6 +27,12 @@ $(BUILDDIR)/cnadd: $(SRCDIR)/cnadd.c $(HEADERS)
 $(BUILDDIR)/cndump: $(SRCDIR)/cndump.c $(HEADERS)
 	$(CC) $(CFLAGS) $(INCLUDES) -o $@ $(SRCDIR)/cndump.c
 
+$(BUILDDIR)/cncount: $(SRCDIR)/cncount.c $(HEADERS)
+	$(CC) $(CFLAGS) $(INCLUDES) -o $@ $(SRCDIR)/cncount.c
+
+$(BUILDDIR)/cndel: $(SRCDIR)/cndel.c $(HEADERS)
+	$(CC) $(CFLAGS) $(INCLUDES) -o $@ $(SRCDIR)/cndel.c
+
 clean:
 	rm -rf $(BUILDDIR)
 
@@ -34,6 +40,8 @@ clean:
 install: $(TARGETS)
 	install -m 755 $(BUILDDIR)/cnadd /usr/local/bin/
 	install -m 755 $(BUILDDIR)/cndump /usr/local/bin/
+	install -m 755 $(BUILDDIR)/cncount /usr/local/bin/
+	install -m 755 $(BUILDDIR)/cndel /usr/local/bin/
 
 uninstall:
-	rm -f /usr/local/bin/cnadd /usr/local/bin/cndump
+	rm -f /usr/local/bin/cnadd /usr/local/bin/cndump /usr/local/bin/cncount /usr/local/bin/cndel

README.md

@@ -0,0 +1,189 @@
+# cnotes
+
+A simple command-line note-taking system written in strict C89/ANSI C for maximum portability.
+
+## Overview
+
+cnotes provides quick, one-line note capture from the terminal. Notes are stored in a simple CSV format and can be displayed, sorted, and filtered.
+
+## Supported Platforms
+
+- Linux/Unix (GCC)
+- macOS (GCC/Clang)
+- Windows (Turbo C++ 3.0, MinGW)
+- DOS 6.22 (Turbo C++ 3.0)
+
+## Building
+
+### Linux/Unix/macOS
+
+```bash
+make
+```
+
+Binaries are placed in the `build/` directory.
+
+### DOS/Windows (Turbo C++ 3.0)
+
+```batch
+make -f MAKEFILE.TC
+```
+
+Or use the batch file if `make` is unavailable:
+
+```batch
+BUILD.BAT
+```
+
+### Installation (Unix-like systems)
+
+```bash
+sudo make install    # installs to /usr/local/bin
+sudo make uninstall  # removes from /usr/local/bin
+```
+
+## Commands
+
+### cnadd
+
+Add a new timestamped note entry.
+
+```bash
+cnadd "Remember to call Bob"
+cnadd -c Work "Meeting at 3pm"
+cnadd -c Personal "Buy groceries"
+```
+
+Options:
+- `-c CATEGORY` - Specify category (max 10 chars, default: "General")
+
+### cndump
+
+Display all notes in a formatted table.
+
+```bash
+cndump              # display all notes
+cndump -d           # sort by date (newest first)
+cndump -c           # sort by category
+cndump -r           # reverse sort order
+cndump -d -r        # sort by date, oldest first
+```
+
+Options:
+- `-d, --date` - Sort by date/time
+- `-c, --category` - Sort by category
+- `-r, --reverse` - Reverse sort order
+
+### cncount
+
+Display note statistics.
+
+```bash
+cncount             # total entry count
+cncount -c          # count by category
+cncount -d          # count by date
+```
+
+Options:
+- `-c, --category` - Show counts per category
+- `-d, --date` - Show counts per date
+
+### cndel
+
+Delete note entries.
+
+```bash
+cndel -n 5          # delete entry at line 5
+cndel -l            # delete the last (most recent) entry
+cndel -d 2025-01-30 # delete all entries from a specific date
+cndel -n 5 -y       # delete without confirmation prompt
+```
+
+Options:
+- `-n LINE_NUMBER` - Delete entry at specified line number
+- `-d DATE` - Delete all entries matching DATE (YYYY-MM-DD)
+- `-l` - Delete the last (most recent) entry
+- `-y` - Skip confirmation prompt
+
+## Configuration
+
+### Notes Location
+
+By default, notes are stored in:
+
+| Platform | Location |
+|----------|----------|
+| Unix/Linux | `~/.local/share/cnotes/cnotes.csv` |
+| Windows | `%USERPROFILE%\.cnotes\cnotes.csv` |
+| DOS | Current directory or `%CNOTES_HOME%\cnotes.csv` |
+
+### Environment Variables
+
+- `CNOTES_PATH` - Override the notes directory location (highest priority)
+- On DOS, set `CNOTES_HOME` if `HOME` is not available
+
+Example:
+```bash
+export CNOTES_PATH=/custom/path/to/notes
+```
+
+### Compile-time Configuration
+
+Override defaults by defining at compile time:
+
+```bash
+gcc -DCNOTES_DIR=\".mynotes\" -DMAX_ENTRIES=1000 ...
+```
+
+## Data Format
+
+Notes are stored in CSV format:
+
+```
+DATE,TIME,CATEGORY  ,"MESSAGE"
+2025-01-30,14:30,Work      ,"Meeting with team"
+2025-01-30,09:15,Personal  ,"Buy groceries"
+```
+
+Fields:
+- Date: `YYYY-MM-DD` (10 chars)
+- Time: `HH:MM` (5 chars)
+- Category: padded to 10 chars
+- Message: quoted, max 125 chars
+
+## TODO
+
+Future commands to implement:
+
+- [ ] **cnfind** - Search notes by keyword, category, or date
+  ```
+  cnfind "meeting"        # search in message text
+  cnfind -c Work          # filter by category
+  cnfind -d 2025-01-30    # filter by date
+  ```
+
+- [ ] **cntail** - Show last N entries (quick view)
+  ```
+  cntail                  # last 5 entries
+  cntail -n 10            # last 10 entries
+  ```
+
+- [ ] **cncat** - List unique categories
+  ```
+  cncat                   # list categories
+  cncat -c                # with counts
+  ```
+
+- [ ] **cnexport** - Export to other formats
+  ```
+  cnexport > notes.txt    # plain text
+  cnexport -t > notes.tsv # tab-separated
+  ```
+
+## License
+
+[Your license here]
+
+## Author
+
+Gregory Gauthier

compile_commands.json

@@ -0,0 +1,22 @@
+[
+  {
+    "directory": ".",
+    "command": "gcc -ansi -Wpedantic -Wall -Wextra -O2 -I include -c src/cnadd.c -o build/cnadd.o",
+    "file": "src/cnadd.c"
+  },
+  {
+    "directory": ".",
+    "command": "gcc -ansi -Wpedantic -Wall -Wextra -O2 -I include -c src/cndump.c -o build/cndump.o",
+    "file": "src/cndump.c"
+  },
+  {
+    "directory": ".",
+    "command": "gcc -ansi -Wpedantic -Wall -Wextra -O2 -I include -c src/cncount.c -o build/cncount.o",
+    "file": "src/cncount.c"
+  },
+  {
+    "directory": ".",
+    "command": "gcc -ansi -Wpedantic -Wall -Wextra -O2 -I include -c src/cndel.c -o build/cndel.o",
+    "file": "src/cndel.c"
+  }
+]

src/cncount.c

@@ -0,0 +1,266 @@
+/*
+ * cncount - Display note statistics
+ */
+
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+#include "platform.h"
+#include "config.h"
+
+#define MAX_LENGTH 500
+#define DATE_LENGTH 10
+#define TIME_LENGTH 5
+#define MAX_UNIQUE 500  /* Max unique categories or dates */
+
+typedef enum {
+    COUNT_TOTAL,
+    COUNT_BY_CATEGORY,
+    COUNT_BY_DATE
+} CountMode;
+
+typedef struct {
+    char key[CATEGORY_LENGTH + 1];
+    int count;
+} CountEntry;
+
+/* Parse date field from CSV line */
+static int parse_date(const char *line, char *date) {
+    if (strlen(line) < DATE_LENGTH) return 0;
+    strncpy(date, line, DATE_LENGTH);
+    date[DATE_LENGTH] = '\0';
+    return 1;
+}
+
+/* Parse category field from CSV line */
+static int parse_category(const char *line, char *category) {
+    const char *ptr;
+    int i;
+
+    /* Skip date and time fields: DATE,TIME,CATEGORY */
+    if (strlen(line) < DATE_LENGTH + 1 + TIME_LENGTH + 1) return 0;
+    ptr = line + DATE_LENGTH + 1 + TIME_LENGTH + 1;
+
+    /* Copy category until comma */
+    i = 0;
+    while (*ptr != ',' && *ptr != '\0' && i < CATEGORY_LENGTH) {
+        category[i++] = *ptr++;
+    }
+    category[i] = '\0';
+
+    /* Trim trailing spaces */
+    while (i > 0 && category[i - 1] == ' ') {
+        category[--i] = '\0';
+    }
+
+    return 1;
+}
+
+/* Find or add a key in the counts array */
+static int find_or_add(CountEntry *counts, int *num_entries, const char *key) {
+    int i;
+
+    /* Search for existing key */
+    for (i = 0; i < *num_entries; i++) {
+        if (strcmp(counts[i].key, key) == 0) {
+            return i;
+        }
+    }
+
+    /* Add new key if room */
+    if (*num_entries >= MAX_UNIQUE) {
+        return -1;
+    }
+
+    strncpy(counts[*num_entries].key, key, CATEGORY_LENGTH);
+    counts[*num_entries].key[CATEGORY_LENGTH] = '\0';
+    counts[*num_entries].count = 0;
+    (*num_entries)++;
+
+    return *num_entries - 1;
+}
+
+/* Comparison function for sorting by key */
+static int compare_by_key(const void *a, const void *b) {
+    const CountEntry *ea = (const CountEntry *)a;
+    const CountEntry *eb = (const CountEntry *)b;
+    return strcmp(ea->key, eb->key);
+}
+
+/* Comparison function for sorting by count (descending) */
+static int compare_by_count(const void *a, const void *b) {
+    const CountEntry *ea = (const CountEntry *)a;
+    const CountEntry *eb = (const CountEntry *)b;
+    return eb->count - ea->count;
+}
+
+int get_cnotes_path(char *buffer, size_t bufsize) {
+    const char *custom_path;
+    const char *home;
+    size_t len;
+
+    custom_path = getenv(CNOTES_PATH_ENV);
+    if (custom_path != NULL && strlen(custom_path) > 0) {
+        if (strlen(custom_path) + strlen(CNOTES_FILE) + 2 > bufsize) {
+            fprintf(stderr, "Error: Path too long\n");
+            return 0;
+        }
+        sprintf(buffer, "%s" PATH_SEP_STR "%s", custom_path, CNOTES_FILE);
+        return 1;
+    }
+
+    home = getenv(HOME_ENV);
+    if (home == NULL) {
+        fprintf(stderr, "Error: %s environment variable not set\n", HOME_ENV);
+        fprintf(stderr, "Hint: Set %s to specify notes directory\n", CNOTES_PATH_ENV);
+        return 0;
+    }
+
+    len = strlen(home);
+    if (strlen(CNOTES_DIR) == 0) {
+        if (len + strlen(CNOTES_FILE) + 2 > bufsize) {
+            fprintf(stderr, "Error: Path too long\n");
+            return 0;
+        }
+        sprintf(buffer, "%s" PATH_SEP_STR "%s", home, CNOTES_FILE);
+    } else {
+        if (len + strlen(CNOTES_DIR) + strlen(CNOTES_FILE) + 3 > bufsize) {
+            fprintf(stderr, "Error: Path too long\n");
+            return 0;
+        }
+        sprintf(buffer, "%s" PATH_SEP_STR "%s" PATH_SEP_STR "%s", home, CNOTES_DIR, CNOTES_FILE);
+    }
+    return 1;
+}
+
+void print_usage(const char *prog_name) {
+    fprintf(stderr, "Usage: %s [-c|--category] [-d|--date]\n", prog_name);
+    fprintf(stderr, "  -c, --category  Count entries by category\n");
+    fprintf(stderr, "  -d, --date      Count entries by date\n");
+    fprintf(stderr, "  (no options)    Show total count only\n");
+}
+
+int main(int argc, char *argv[]) {
+    int i;
+    FILE *notesfile;
+    char file_path[600];
+    char line[MAX_LENGTH + 1];
+    char key[CATEGORY_LENGTH + 1];
+    int total_count = 0;
+    CountMode mode = COUNT_TOTAL;
+    CountEntry *counts;
+    int num_entries = 0;
+    int idx;
+
+    /* Parse command line arguments */
+    for (i = 1; i < argc; i++) {
+        if (strcmp(argv[i], "-c") == 0 || strcmp(argv[i], "--category") == 0) {
+            if (mode != COUNT_TOTAL) {
+                fprintf(stderr, "cncount: cannot specify multiple count modes\n");
+                print_usage(argv[0]);
+                return 1;
+            }
+            mode = COUNT_BY_CATEGORY;
+        }
+        else if (strcmp(argv[i], "-d") == 0 || strcmp(argv[i], "--date") == 0) {
+            if (mode != COUNT_TOTAL) {
+                fprintf(stderr, "cncount: cannot specify multiple count modes\n");
+                print_usage(argv[0]);
+                return 1;
+            }
+            mode = COUNT_BY_DATE;
+        }
+        else if (strcmp(argv[i], "-h") == 0 || strcmp(argv[i], "--help") == 0) {
+            print_usage(argv[0]);
+            return 0;
+        }
+        else {
+            fprintf(stderr, "cncount: unknown option '%s'\n", argv[i]);
+            print_usage(argv[0]);
+            return 1;
+        }
+    }
+
+    /* Allocate counts array if needed */
+    counts = NULL;
+    if (mode != COUNT_TOTAL) {
+        counts = (CountEntry *)malloc(MAX_UNIQUE * sizeof(CountEntry));
+        if (counts == NULL) {
+            fprintf(stderr, "Error: Cannot allocate memory\n");
+            return 1;
+        }
+    }
+
+    /* Get cnotes file path */
+    if (!get_cnotes_path(file_path, sizeof(file_path))) {
+        if (counts) free(counts);
+        return 1;
+    }
+
+    notesfile = fopen(file_path, "r");
+    if (notesfile == NULL) {
+        fprintf(stderr, "Error: Cannot open file '%s'\n", file_path);
+        fprintf(stderr, "Hint: Use 'cnadd' to create your first entry\n");
+        if (counts) free(counts);
+        return 1;
+    }
+
+    /* Read and count entries */
+    while (fgets(line, MAX_LENGTH, notesfile) != NULL) {
+        /* Skip empty lines */
+        if (strlen(line) < DATE_LENGTH) continue;
+
+        total_count++;
+
+        if (mode == COUNT_BY_DATE) {
+            if (parse_date(line, key)) {
+                idx = find_or_add(counts, &num_entries, key);
+                if (idx >= 0) {
+                    counts[idx].count++;
+                }
+            }
+        }
+        else if (mode == COUNT_BY_CATEGORY) {
+            if (parse_category(line, key)) {
+                idx = find_or_add(counts, &num_entries, key);
+                if (idx >= 0) {
+                    counts[idx].count++;
+                }
+            }
+        }
+    }
+    fclose(notesfile);
+
+    /* Print results */
+    if (mode == COUNT_TOTAL) {
+        printf("Total entries: %d\n", total_count);
+    }
+    else {
+        /* Sort results */
+        if (mode == COUNT_BY_DATE) {
+            qsort(counts, num_entries, sizeof(CountEntry), compare_by_key);
+        } else {
+            qsort(counts, num_entries, sizeof(CountEntry), compare_by_count);
+        }
+
+        /* Print header */
+        if (mode == COUNT_BY_DATE) {
+            printf("%-12s %s\n", "Date", "Count");
+            printf("%-12s %s\n", "----------", "-----");
+        } else {
+            printf("%-12s %s\n", "Category", "Count");
+            printf("%-12s %s\n", "----------", "-----");
+        }
+
+        /* Print counts */
+        for (i = 0; i < num_entries; i++) {
+            printf("%-12s %d\n", counts[i].key, counts[i].count);
+        }
+
+        printf("%-12s %s\n", "----------", "-----");
+        printf("%-12s %d\n", "Total", total_count);
+    }
+
+    if (counts) free(counts);
+    return 0;
+}

src/cndel.c

@@ -0,0 +1,340 @@
+/*
+ * cndel - Delete note entries
+ */
+
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+#include "platform.h"
+#include "config.h"
+
+#define MAX_LENGTH 500
+#define DATE_LENGTH 10
+#define TIME_LENGTH 5
+
+int get_cnotes_path(char *buffer, size_t bufsize) {
+    const char *custom_path;
+    const char *home;
+    size_t len;
+
+    custom_path = getenv(CNOTES_PATH_ENV);
+    if (custom_path != NULL && strlen(custom_path) > 0) {
+        if (strlen(custom_path) + strlen(CNOTES_FILE) + 2 > bufsize) {
+            fprintf(stderr, "Error: Path too long\n");
+            return 0;
+        }
+        sprintf(buffer, "%s" PATH_SEP_STR "%s", custom_path, CNOTES_FILE);
+        return 1;
+    }
+
+    home = getenv(HOME_ENV);
+    if (home == NULL) {
+        fprintf(stderr, "Error: %s environment variable not set\n", HOME_ENV);
+        fprintf(stderr, "Hint: Set %s to specify notes directory\n", CNOTES_PATH_ENV);
+        return 0;
+    }
+
+    len = strlen(home);
+    if (strlen(CNOTES_DIR) == 0) {
+        if (len + strlen(CNOTES_FILE) + 2 > bufsize) {
+            fprintf(stderr, "Error: Path too long\n");
+            return 0;
+        }
+        sprintf(buffer, "%s" PATH_SEP_STR "%s", home, CNOTES_FILE);
+    } else {
+        if (len + strlen(CNOTES_DIR) + strlen(CNOTES_FILE) + 3 > bufsize) {
+            fprintf(stderr, "Error: Path too long\n");
+            return 0;
+        }
+        sprintf(buffer, "%s" PATH_SEP_STR "%s" PATH_SEP_STR "%s", home, CNOTES_DIR, CNOTES_FILE);
+    }
+    return 1;
+}
+
+/* Get temporary file path */
+int get_temp_path(char *buffer, size_t bufsize, const char *original_path) {
+    size_t len = strlen(original_path);
+    if (len + 5 > bufsize) {
+        fprintf(stderr, "Error: Path too long\n");
+        return 0;
+    }
+    sprintf(buffer, "%s.tmp", original_path);
+    return 1;
+}
+
+/* Parse and display a line for confirmation */
+void display_entry(int line_num, const char *line) {
+    char date[DATE_LENGTH + 1];
+    char time_str[TIME_LENGTH + 1];
+    char category[CATEGORY_LENGTH + 1];
+    const char *ptr;
+    const char *msg_start;
+    const char *msg_end;
+    int i;
+
+    /* Parse date */
+    if (strlen(line) < DATE_LENGTH) return;
+    strncpy(date, line, DATE_LENGTH);
+    date[DATE_LENGTH] = '\0';
+
+    /* Parse time */
+    ptr = line + DATE_LENGTH + 1;
+    if (strlen(ptr) < TIME_LENGTH) return;
+    strncpy(time_str, ptr, TIME_LENGTH);
+    time_str[TIME_LENGTH] = '\0';
+
+    /* Parse category */
+    ptr = ptr + TIME_LENGTH + 1;
+    i = 0;
+    while (*ptr != ',' && *ptr != '\0' && i < CATEGORY_LENGTH) {
+        category[i++] = *ptr++;
+    }
+    category[i] = '\0';
+    /* Trim trailing spaces */
+    while (i > 0 && category[i - 1] == ' ') {
+        category[--i] = '\0';
+    }
+
+    /* Find message (quoted) */
+    msg_start = strchr(ptr, '"');
+    if (msg_start) {
+        msg_start++;
+        msg_end = strchr(msg_start, '"');
+        if (msg_end) {
+            printf("  Line %d: [%s %s] [%s] ", line_num, date, time_str, category);
+            /* Print message without trailing quote */
+            while (msg_start < msg_end) {
+                putchar(*msg_start++);
+            }
+            putchar('\n');
+            return;
+        }
+    }
+
+    /* Fallback: just show the raw line */
+    printf("  Line %d: %s", line_num, line);
+}
+
+void print_usage(const char *prog_name) {
+    fprintf(stderr, "Usage: %s -n LINE_NUMBER [-y]\n", prog_name);
+    fprintf(stderr, "       %s -d DATE [-y]\n", prog_name);
+    fprintf(stderr, "       %s -l [-y]\n", prog_name);
+    fprintf(stderr, "\n");
+    fprintf(stderr, "Options:\n");
+    fprintf(stderr, "  -n LINE_NUMBER  Delete entry at specified line number\n");
+    fprintf(stderr, "  -d DATE         Delete all entries matching DATE (YYYY-MM-DD)\n");
+    fprintf(stderr, "  -l              Delete the last (most recent) entry\n");
+    fprintf(stderr, "  -y              Skip confirmation prompt\n");
+}
+
+int main(int argc, char *argv[]) {
+    int i;
+    FILE *infile;
+    FILE *outfile;
+    char file_path[600];
+    char temp_path[610];
+    char line[MAX_LENGTH + 1];
+    int line_num;
+    int target_line = -1;
+    char *target_date = NULL;
+    int delete_last = 0;
+    int skip_confirm = 0;
+    int total_lines = 0;
+    int deleted_count = 0;
+    int confirm;
+    char response[10];
+
+    /* Parse command line arguments */
+    for (i = 1; i < argc; i++) {
+        if (strcmp(argv[i], "-n") == 0) {
+            if (i + 1 >= argc) {
+                fprintf(stderr, "cndel: -n requires a line number\n");
+                print_usage(argv[0]);
+                return 1;
+            }
+            target_line = atoi(argv[++i]);
+            if (target_line < 1) {
+                fprintf(stderr, "cndel: invalid line number '%s'\n", argv[i]);
+                return 1;
+            }
+        }
+        else if (strcmp(argv[i], "-d") == 0) {
+            if (i + 1 >= argc) {
+                fprintf(stderr, "cndel: -d requires a date (YYYY-MM-DD)\n");
+                print_usage(argv[0]);
+                return 1;
+            }
+            target_date = argv[++i];
+            if (strlen(target_date) != DATE_LENGTH) {
+                fprintf(stderr, "cndel: invalid date format '%s' (use YYYY-MM-DD)\n", target_date);
+                return 1;
+            }
+        }
+        else if (strcmp(argv[i], "-l") == 0) {
+            delete_last = 1;
+        }
+        else if (strcmp(argv[i], "-y") == 0) {
+            skip_confirm = 1;
+        }
+        else if (strcmp(argv[i], "-h") == 0 || strcmp(argv[i], "--help") == 0) {
+            print_usage(argv[0]);
+            return 0;
+        }
+        else {
+            fprintf(stderr, "cndel: unknown option '%s'\n", argv[i]);
+            print_usage(argv[0]);
+            return 1;
+        }
+    }
+
+    /* Validate options */
+    if (target_line < 0 && target_date == NULL && !delete_last) {
+        fprintf(stderr, "cndel: must specify -n LINE_NUMBER, -d DATE, or -l\n");
+        print_usage(argv[0]);
+        return 1;
+    }
+
+    if ((target_line > 0) + (target_date != NULL) + delete_last > 1) {
+        fprintf(stderr, "cndel: cannot combine -n, -d, and -l options\n");
+        print_usage(argv[0]);
+        return 1;
+    }
+
+    /* Get file paths */
+    if (!get_cnotes_path(file_path, sizeof(file_path))) {
+        return 1;
+    }
+
+    if (!get_temp_path(temp_path, sizeof(temp_path), file_path)) {
+        return 1;
+    }
+
+    /* If deleting last entry, first count total lines */
+    if (delete_last) {
+        infile = fopen(file_path, "r");
+        if (infile == NULL) {
+            fprintf(stderr, "Error: Cannot open file '%s'\n", file_path);
+            return 1;
+        }
+        while (fgets(line, MAX_LENGTH, infile) != NULL) {
+            if (strlen(line) >= DATE_LENGTH) {
+                total_lines++;
+            }
+        }
+        fclose(infile);
+
+        if (total_lines == 0) {
+            fprintf(stderr, "cndel: no entries to delete\n");
+            return 1;
+        }
+        target_line = total_lines;
+    }
+
+    /* First pass: show what will be deleted and count matches */
+    infile = fopen(file_path, "r");
+    if (infile == NULL) {
+        fprintf(stderr, "Error: Cannot open file '%s'\n", file_path);
+        return 1;
+    }
+
+    printf("The following entries will be deleted:\n\n");
+    line_num = 0;
+    while (fgets(line, MAX_LENGTH, infile) != NULL) {
+        if (strlen(line) < DATE_LENGTH) continue;
+        line_num++;
+
+        if (target_line > 0 && line_num == target_line) {
+            display_entry(line_num, line);
+            deleted_count++;
+        }
+        else if (target_date != NULL && strncmp(line, target_date, DATE_LENGTH) == 0) {
+            display_entry(line_num, line);
+            deleted_count++;
+        }
+    }
+    fclose(infile);
+
+    if (deleted_count == 0) {
+        if (target_line > 0) {
+            fprintf(stderr, "cndel: line %d does not exist (file has %d entries)\n",
+                    target_line, line_num);
+        } else {
+            fprintf(stderr, "cndel: no entries found matching date '%s'\n", target_date);
+        }
+        return 1;
+    }
+
+    printf("\n%d entry(s) will be deleted.\n", deleted_count);
+
+    /* Confirm deletion */
+    if (!skip_confirm) {
+        printf("Are you sure? [y/N]: ");
+        fflush(stdout);
+
+        if (fgets(response, sizeof(response), stdin) == NULL) {
+            printf("Aborted.\n");
+            return 1;
+        }
+
+        confirm = (response[0] == 'y' || response[0] == 'Y');
+        if (!confirm) {
+            printf("Aborted.\n");
+            return 0;
+        }
+    }
+
+    /* Second pass: copy all lines except deleted ones to temp file */
+    infile = fopen(file_path, "r");
+    if (infile == NULL) {
+        fprintf(stderr, "Error: Cannot open file '%s'\n", file_path);
+        return 1;
+    }
+
+    outfile = fopen(temp_path, "w");
+    if (outfile == NULL) {
+        fprintf(stderr, "Error: Cannot create temporary file '%s'\n", temp_path);
+        fclose(infile);
+        return 1;
+    }
+
+    line_num = 0;
+    deleted_count = 0;
+    while (fgets(line, MAX_LENGTH, infile) != NULL) {
+        if (strlen(line) < DATE_LENGTH) {
+            /* Preserve empty/invalid lines as-is */
+            fputs(line, outfile);
+            continue;
+        }
+        line_num++;
+
+        if (target_line > 0 && line_num == target_line) {
+            deleted_count++;
+            continue;  /* Skip this line */
+        }
+        else if (target_date != NULL && strncmp(line, target_date, DATE_LENGTH) == 0) {
+            deleted_count++;
+            continue;  /* Skip this line */
+        }
+
+        /* Keep this line */
+        fputs(line, outfile);
+    }
+
+    fclose(infile);
+    fclose(outfile);
+
+    /* Replace original with temp file */
+    if (remove(file_path) != 0) {
+        fprintf(stderr, "Error: Cannot remove original file\n");
+        remove(temp_path);
+        return 1;
+    }
+
+    if (rename(temp_path, file_path) != 0) {
+        fprintf(stderr, "Error: Cannot rename temporary file\n");
+        return 1;
+    }
+
+    printf("Deleted %d entry(s).\n", deleted_count);
+    return 0;
+}