a daily log program. Customize and compile.

dl.c

/*
 Created by John Boyle on 10 January 2017.
 Updated 11 January 2017: use Markdown output, use ncurses.
 */

#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <time.h>
#include <ncurses.h>

#define PURPLE "\033[1;35m"
#define RED "\033[1;31m"
#define GREEN "\033[1;32m"
#define BLUE "\033[1;34m"
/* turns off the colors */
#define NC "\033[0m"

#define LOGFILE "/tmp/daily-log.txt"

char * activities[4] = {"play guitar", "figure sketch", "read ocean book", "yoga"};
char date_buf[1024];
char line_buf[1024];
int response;

int main(int argc, char * argv[]) {
    size_t N_activity = sizeof(activities)/sizeof(size_t);

    /* print list of activities if called as "dl list" */
    if (argv[1] && !strcmp("list", argv[1])) {
        fprintf(stderr, "Activities:\n");
        for (size_t ia = 0; ia < N_activity; ia++) {
            fprintf(stderr, "%s%s%s\n", BLUE, activities[ia], NC);
        }
        exit(EXIT_SUCCESS);
    }

    initscr();
    int H, W;
    getmaxyx(stdscr, H, W);

    /* get the date */
    time_t current_time = time(NULL);
    struct tm * t = localtime(&current_time);
    strftime(date_buf, sizeof(date_buf), "%e %B %Y", t);

    /* ask this b/c I often log for the previous day's activities */
    int row = 4;
    mvprintw(row, 0, "Entry date: %s", date_buf);
    mvprintw(row + 1, 0, "Is that correct? (y/n)");
    response = getch();

    if ('n' == response) {
        /* only accept a y/n here b/c this is important to get right */
        do {
            move(row + 2, 0); clrtoeol();
            mvprintw(row + 2, 0, "Should it be yesterday? (y/n) ");
            response = getch();
        } while (response != 'y' && response != 'n');
        if ('y' == response) {
            t->tm_mday -= 1;
            strftime(date_buf, sizeof(date_buf), "%e %B %Y", t);

            clear();
            mvprintw(row, 0, "Log entry date will be %s\n", date_buf);
            getch();
            clear();
        } else if ('n' == response) {
            clear();
            mvprintw(row, 0, "Changing it to a date other than yesterday not yet supported.");
            mvprintw(row + 1, 0, "Log entry date will still be %s\n", date_buf);
            mvprintw(row + 2, 0, "Press any key to continue...");
            getch();
            clear();
        }
    }

    /* start making the log */
    FILE * fh_log = fopen(LOGFILE, "a");
    /* if error, drop out of curses and give msg */
    if (!fh_log) {
        endwin();
        fprintf(stderr, "%s %sERROR%s: failed to open log file %s\n", argv[0], RED, NC, LOGFILE);
        exit(EXIT_FAILURE);
    }

    fprintf(fh_log, "## %s\n", date_buf);

    /* ask about each activity */
    for (size_t ia = 0; ia < N_activity; ia++) {
        move(row, 0); clrtobot();
        mvprintw(row, 0, "Did you %s? (y/n) ", activities[ia]);
        response = getch();

        mvprintw(row + 1, 0, "Write an optional note about it:");
        move(row + 3, 5);
        getnstr(line_buf, sizeof(line_buf));

        /* print the activity name before the note */
        fprintf(fh_log, "* %s\n", activities[ia]);
        if ('y' == response) {
            fprintf(fh_log, "  - Yes. %s\n", line_buf);
        } else if ('n' == response) {
            fprintf(fh_log, "  - Not today. %s\n", line_buf);
        } else {
            fprintf(fh_log, "  -    \n");
        }
    }
    fprintf(fh_log, "\n");
    
    fclose(fh_log);
    endwin();
    return(EXIT_SUCCESS);
}

macOS: compile ncurses version with
cc dl.c -lncurses -o dl

Probably works for any Linux too