rewrote mark in c.

src/mark.c

@@ -0,0 +1,86 @@
+#include <stdio.h>
+#include <string.h>
+#include <unistd.h>
+#include <limits.h>
+#include <stdlib.h>
+
+// Displays error message upon improper usage.
+void error() {
+    printf("\nImproper usage: mark { -ls | -rm [ keyword(s) ] }\n"
+           "    Usage:\n"
+           "        mark\n"
+           "        mark -ls\n"
+           "        mark -rm [ keyword ]\n"
+           "        mark -h\n"
+           "        mark --help"
+           );
+}
+
+// Displays help message.
+void help() {
+    printf("\nCreate and manage persistent bookmarks in the terminal.\n"
+           "Usage:\n"
+           "    mark\n"
+           "    mark -ls\n"
+           "    mark -rm [ keyword ]\n"
+           "    mark -h\n"
+           "    mark --help"
+           );
+}
+
+// Lists all bookmarks in file.
+void list(FILE * f) {
+    int c;
+    printf("Bookmarks:\n");
+    while(1) {
+        c = fgetc(f);
+        if(feof(f)) break;
+        printf("%c", c);
+    }
+}
+
+// Removes a bookmark from the file.
+void removeMark(FILE * f, char *argv[]) {
+    printf("remove mark function not implemented. received input to remove: %s.", argv[2]); // TODO: Need to implement.
+}
+
+int main(int argc, char *argv[]) {
+    char * bookmarksFile = strcat(getenv("HOME"), "/.bookmarks");
+    FILE * f = fopen(bookmarksFile, "a+");
+
+    // Unable to access file.
+    if(f == NULL) {
+        printf("Error accessing file located at %s.", bookmarksFile);
+        return 1;
+    }
+
+    // Invalid number of arguments.
+    else if(argc > 2 && strcmp(argv[1], "-rm") != 0) {
+        error();
+        return 1;
+    }
+
+    // Append the current directory to the bookmarks file.
+    else if(argc == 1) {
+        char cwd[PATH_MAX];
+        fprintf(f, getcwd(cwd, sizeof(cwd)));
+        printf("Successfully bookmarked %s.", cwd);
+    }
+
+    // Display help.
+    else if(strcmp(argv[1], "-h") == 0 || strcmp(argv[1], "--help") == 0) help();
+
+    // List bookmarks.
+    else if(strcmp(argv[1], "-ls") == 0) list(f);
+
+    else if(strcmp(argv[1], "-rm") == 0) removeMark(f, argv);
+
+    // Invalid argument.
+    else {
+        error();
+        return 1;
+    }
+
+    fclose(f);
+    return 0;
+}