fix ls and add start of ed

10 files changed, 1322 insertions, 88 deletions

diff --git a/Makefile b/Makefile
index 28e8e07..a2be56b 100644
--- a/Makefile
+++ b/Makefile
@@ -19,6 +19,7 @@ EOF: clean build
 dirs:
 	mkdir -p ./$(BIN)
 	mkdir -p ./$(BIN)/src
+	mkdir -p ./$(BIN)/src/util
 	mkdir -p ./$(BIN)/src/commands
 
 run: build
diff --git a/src/command.h b/src/command.h
index 0b7b8ad..fb1acb3 100644
--- a/src/command.h
+++ b/src/command.h
@@ -1,4 +1,4 @@
-#include "shared.h"
+#include "util/shared.h"
 
 #include <stdint.h>
 #include <stdlib.h>
@@ -19,3 +19,4 @@ COMMAND_EMPTY(user_id);
 COMMAND(ls);
 COMMAND(tail);
 COMMAND(head);
+COMMAND(ed);
diff --git a/src/commands/cat.c b/src/commands/cat.c
index 8e22706..dd1a732 100644
--- a/src/commands/cat.c
+++ b/src/commands/cat.c
@@ -2,6 +2,7 @@
 
 #include <ctype.h>
 #include <errno.h>
+#include <stdio.h>
 #include <string.h>
 #include <sys/stat.h>
 
@@ -90,18 +91,26 @@ COMMAND(cat) {
     flags.change_tabs = false;
     flags.end_lines_dollar = false;
 
+    int start = 0;
+
     for (int i = 0; i < argc; i++) {
         if (!prefix("-", argv[i])) {
             continue;
         }
 
+        if (streql("-", argv[i])) {
+            break;
+        }
+
         if (streql("--help", argv[i])) {
             help();
         }
 
-        size_t len = strlen(argv[i] + 1);
-        for (size_t j = 0; j < len; j++) {
-            char c = argv[i][j + 1];
+        start++;
+
+        size_t len = strlen(argv[i]);
+        for (size_t j = 1; j < len; j++) {
+            char c = argv[i][j];
             switch (c) {
                 case 'n':
                     flags.number_lines = true;
@@ -131,33 +140,19 @@ COMMAND(cat) {
         } 
     }
 
-    bool files = false;
-    for (int i = 0; i < argc; i++) {
-        if (streql("-", argv[i])) {
-            files = true;
-            cat_file(stdin, flags);
-        } else if (prefix("-", argv[i])) {
-            continue;
-        } else {
-            files = true;
-            struct stat s;
-            if (stat(argv[i], &s) < 0) {
-                printf("error: failed to read %s: %s\n", argv[i], strerror(errno));
-                continue;
-            }
-            if (!S_ISREG(s.st_mode)) {
-                printf("error: %s is not a file\n", argv[i]);
-                continue;
-            }
-            FILE* in = get_file(argv[i], "r");
-            cat_file(in, flags);
-            fclose(in);
-        }
-    }
+    int arg_len = argc - start;
 
-    if (!files) {
+    if (arg_len < 1) {
         cat_file(stdin, flags);
+        return EXIT_SUCCESS;
     }
-    
+
+    for (int i = start; i < argc; i++) {
+        FILE* in = get_file(argv[i], "r");
+        cat_file(in, flags);
+        if (in != stdin)
+            fclose(in);
+    }
+
     return EXIT_SUCCESS;
 }
diff --git a/src/commands/ed.c b/src/commands/ed.c
new file mode 100644
index 0000000..2082ef6
--- /dev/null
+++ b/src/commands/ed.c
@@ -0,0 +1,528 @@
+#include "../command.h"
+#include "../util//regex.h"
+
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+
+#define INPUT_LEN 1024
+
+static char** lines = NULL;
+static unsigned long line_capacity;
+static unsigned long line_count;
+static unsigned long line_current;
+static bool pending_writes;
+
+enum LineAddressType {
+    INDEX,
+    RANGE,
+    SET,
+};
+
+struct LineAddress {
+    enum LineAddressType type;
+    union {
+        struct {
+            long int i;
+        } index;
+        struct {
+            long int a;
+            long int b;
+        } range;
+        struct {
+            long int* b;
+            unsigned long c;
+            unsigned long s;
+        } set;
+    } data;
+    bool empty;
+};
+
+enum RegexDirection {
+    BEFORE,
+    AFTER,
+    ALL
+};
+
+static bool parse_regex(char** end, struct LineAddress* address, enum RegexDirection dir) {
+    char c;
+    char* index = *end;
+    char* regex_str = index;
+    while(true) {
+        c = *(index++);
+        if (c == '\0') {
+            fprintf(stderr, "error: missing regex after %c\n", dir == BEFORE ? '?' : '/');
+            return false;
+        }
+        if (c == (dir == BEFORE ? '?' : '/')) {
+            *(index - 1) = '\0';
+            break;
+        }
+    }
+    unsigned long cap = 8;
+    unsigned long siz = 0;
+    long int* buf = malloc(cap * sizeof(unsigned long));
+
+    re_t regex = re_compile(regex_str);
+    unsigned long i = (dir == ALL ? 0 : line_current);
+    unsigned long until = (dir == BEFORE ? 0 : line_count - 1);
+    for (; (dir == BEFORE ? i >= until : i < until); dir == BEFORE ? i-- : i++) {
+        int len;
+        if (re_matchp(regex, lines[i], &len) == -1) {
+            if (dir == BEFORE && i == 0) break;
+            continue;
+        }
+        if (cap == siz) {
+            cap *= 2;
+            buf = realloc(buf, cap * sizeof(unsigned long));
+        }
+        buf[siz] = i;
+        siz++;
+        if (dir == BEFORE && i == 0) break;
+    }
+
+    address->type = SET;
+    address->data.set.s = siz;
+    address->data.set.c = cap;
+    address->data.set.b = buf;
+    *end = index;
+    return true;
+}
+
+static bool read_address(char** command, bool whitespace, struct LineAddress* a) {
+    char* index = *command;
+    struct LineAddress address;
+    memset(&address, 0, sizeof(struct LineAddress));
+    
+    address.empty = false;
+    if (strlen(*command) < 1) {
+        address.type = INDEX;
+        address.data.index.i = line_current + 1;
+        if (line_current >= line_count) line_current = line_count - 1;
+        *a = address;
+        return true;
+    }
+
+    char* end_pre;
+    long int n_pre = strtol(index, &end_pre, 10) - 1;
+    if (end_pre == index) {
+        n_pre = -1;
+    } else {
+        if (n_pre < 0) {
+            fprintf(stderr, "error: input cannot be negative\n");
+            return false;
+        }
+        index = end_pre;
+    }
+    
+    char pre = *(index++);
+    switch (pre) {
+        case '.':
+            address.type = INDEX;
+            address.data.index.i = line_current;
+            break;
+        case '$':
+            address.type = INDEX;
+            address.data.index.i = line_count - 1;
+            break;
+        case '-':
+        case '^': {
+            address.type = INDEX;
+            char* end;
+            long int n = strtol(index, &end, 10) - 1;
+            if (n < 0) {
+                fprintf(stderr, "error: input cannot be negative\n");
+                return false;
+            }
+            if (index == end) {
+                address.data.index.i = line_current - 1;
+            } else {
+                address.data.index.i = line_current - n;
+            }
+            if (address.data.index.i < 0) {
+                fprintf(stderr, "error: line number %ld does not exist\n", address.data.index.i + 1);
+                return false;
+            }
+            break;
+        }
+        case '+': {
+            address.type = INDEX;
+            char* end;
+            long int n = strtol(index, &end, 10) - 1;
+            if (n < 0) {
+                fprintf(stderr, "error: input cannot be negative\n");
+                return false;
+            }
+            if (index == end) {
+                address.data.index.i = line_current + 1;
+            } else {
+                address.data.index.i = line_current + n;
+            }
+            if (address.data.index.i >= (long int) line_count) {
+                fprintf(stderr, "error: line number %ld does not exist\n", address.data.index.i + 1);
+                return false;
+            }
+            break;
+        }
+        case '%':
+            address.type = RANGE;
+            address.data.range.a = 0;
+            address.data.range.b = line_count - 1;
+            break;
+        case ';':
+            address.type = RANGE;
+            address.data.range.a = line_current;
+            address.data.range.b = line_count - 1;
+            break;
+        case '/': 
+            if (!parse_regex(&index, &address, AFTER)) return false;
+            break;
+        case '?':
+            if (!parse_regex(&index, &address, BEFORE)) return false;
+            break;
+        default: {
+            index--;
+            if (n_pre == -1) {
+                address.type = INDEX;
+                address.data.index.i = line_current;
+                address.empty = true;
+                break;
+            } else if (whitespace) {
+                address.type = INDEX;
+                address.data.index.i = line_current + n_pre;
+            } else {
+                address.type = INDEX;
+                address.data.index.i = n_pre;
+            }
+            if (address.data.index.i < 0 || address.data.index.i >= (long int) line_count) {
+                fprintf(stderr, "error: line number %ld does not exist\n", address.data.index.i + 1);
+                return false;
+            }
+        }
+    }
+    *command = index;
+    *a = address;
+    return true;
+}
+
+static void free_address (struct LineAddress address) {
+    if (address.type != SET) return;
+    free(address.data.set.b);
+}
+
+static void free_data() {
+    if (lines == NULL) return;
+    for (unsigned long i = 0; i < line_count; i++) 
+        free(lines[i]);
+    free(lines);
+    lines = NULL;
+}
+
+static void load_empty() {
+    free_data();
+
+    line_capacity = 8;
+    lines = malloc(sizeof(char*) * line_capacity);
+
+    line_count = 0;
+    line_current = 0;
+    pending_writes = false;
+}
+
+static void get_input(FILE* file, char*** buffer, unsigned long* capacity, unsigned long* size) {
+    unsigned long cap = 8;
+    unsigned long siz = 0;
+    char** buf = malloc(sizeof(char*) * cap);
+
+    char* line = NULL;
+    size_t offset = 0;
+    
+    clearerr(stdin);
+    while (getline(&line, &offset, file) != -1) {
+        if (cap == siz) {
+            cap *= 2;
+            buf = realloc(buf, sizeof(char*) * cap);
+        }
+        buf[siz] = line;
+        siz++;
+        line = NULL;
+    }
+
+    free(line);
+
+    *buffer = buf;
+    *capacity = cap;
+    *size = siz;
+}
+
+int ed_getline(char *buf, size_t size) {
+    size_t i = 0;
+    int ch;
+    clearerr(stdin);
+    while ((ch = getchar()) != EOF) {  // Read until EOF ...
+        if (i + 1 < size) {
+            buf[i++] = ch;
+        }
+        if (ch == '\n') {  // ... or end of line
+            break;  
+        }
+    } 
+    buf[i] = '\0';
+    if (i == 0) { 
+        return EOF;
+    }
+    return i;
+}
+
+static void load_file(FILE* file) {
+    free_data();
+    line_current = 0;
+    get_input(file, &lines, &line_capacity, &line_count);
+    if (file != stdin)
+        fclose(file);
+}
+
+static bool check_if_sure() {
+    if (!pending_writes) {
+        return true;
+    }
+
+    printf("Do you really want to quit? ");
+    fflush(stdout);
+
+    char buf[INPUT_LEN];
+    if (ed_getline(buf, INPUT_LEN) == EOF) {
+        putchar('\n');
+        return false;
+    }
+
+    return prefix("y", buf);
+}
+
+static bool skip_whitespace(char** index) {
+    char c;
+    bool w = false;
+    while (c = **index, c == ' ' || c == '\t') { (*index)++; w = true; }
+    return w;
+}
+
+static void expand(unsigned long count) {
+    if (count < line_capacity) return;
+    line_capacity *= 2;
+    if (count > line_capacity) line_capacity = count;
+    lines = realloc(lines, line_capacity * sizeof(char*));
+}
+
+static void append_lines(unsigned long index, char** new, unsigned long new_len) {
+    if (new_len < 1) return;
+    pending_writes = true;
+    expand(line_count + new_len);
+    if (index + 1 <= line_count)
+        memmove(&lines[index+new_len], &lines[index], sizeof(char*) * (line_count - index));
+    memcpy(&lines[index], new, sizeof(char*) * new_len);
+    line_count += new_len;
+}
+
+static void delete_lines(unsigned long a, unsigned long b) {
+    if (b < a) return;
+    pending_writes = true;
+    for (unsigned long i = a; i <= b; i++) {
+        free(lines[i]);
+    }
+    if (b == line_count - 1) {
+        line_count = a;
+        return;
+    }
+    memmove(&lines[a], &lines[b+1], sizeof(char*) * (line_count - (b + 1)));
+    line_count -= (b - a) + 1;
+    line_current = a;
+    if (line_current >= line_count) line_current = line_count - 1;
+}
+
+static bool handle_append(struct LineAddress* address) {
+    if (address->type != INDEX) {
+        fprintf(stderr, "error: append command requires index addressing\n");
+        return false;
+    }
+    if (line_count == 0) {
+        address->data.index.i = -1;
+    }
+    char** buf;
+    unsigned long cap, size;
+    get_input(stdin, &buf, &cap, &size);
+    if (size > 0) {
+        append_lines(address->data.index.i + 1, buf, size);
+    }
+    line_current += size;
+    free(buf);
+    return true;
+}
+
+static bool handle_delete(struct LineAddress* address) {
+    if (address->empty && address->data.index.i >= (long int) line_count) {
+        fprintf(stderr, "error: line number %ld does not exist\n", address->data.index.i + 1);
+        return false;
+    }
+    if (address->type == INDEX) {
+        delete_lines(address->data.index.i, address->data.index.i);
+    } else if (address->type == RANGE) {
+        delete_lines(address->data.range.a, address->data.range.b);
+    } else if (address->type == SET) {
+        for (unsigned long i = 0; i < address->data.set.s; i++) {
+            delete_lines(address->data.set.b[i], address->data.set.b[i]);
+        }
+    }
+    return true;
+}
+
+static void prompt() {
+    printf("%ld: ", line_current + 1);
+    fflush(stdout);
+
+    char buf[INPUT_LEN];
+    if (ed_getline(buf, INPUT_LEN) == EOF) { putchar('\n'); return; }
+    if (buf[0] == '\0') { putchar('\n'); return; }
+
+    char* index = &buf[0];
+    bool whitespace = skip_whitespace(&index);
+
+    struct LineAddress address;
+    if (!read_address(&index, whitespace, &address)) return;
+
+    char cmd = *(index++);
+    
+    if (cmd == ',') {
+        if (address.type != INDEX) {
+            fprintf(stderr, "error: comma range addressing requires two index addresses\n");
+            free_address(address);
+            return;
+        }
+        struct LineAddress address2;
+        whitespace = skip_whitespace(&index);
+        if (!read_address(&index, whitespace, &address2)) {
+            free_address(address);
+            return;
+        }
+        if (address2.type != INDEX) {
+            fprintf(stderr, "error: comma range addressing requires two index addresses\n");
+            free_address(address);
+            free_address(address2);
+            return;
+        }
+        address.type = RANGE;
+        address.data.range.a = address.data.index.i; // cursed
+        address.data.range.b = address2.data.index.i;
+
+        cmd = *(index++);
+    }
+
+    if (address.type == RANGE && address.data.range.a > address.data.range.b) {
+        fprintf(stderr, "error: range addressing must be in ascending order\n");
+        free_address(address);
+        return;
+    }
+
+    switch (cmd) {
+        case '\n':
+        case '\0':
+            if (address.empty) {
+                if (line_current == line_count) {
+                    fprintf(stderr, "error: line number %ld does not exist\n", line_current + 1);
+                    break;
+                } else if (line_current + 1 == line_count) {
+                    fprintf(stderr, "error: line number %ld does not exist\n", line_current + 2);
+                    break;
+                } else {
+                    line_current++;
+                }
+                printf("%s", lines[line_current]);
+                break;
+            }
+            if (address.type == INDEX) {
+                line_current = address.data.index.i;
+            } else if (address.type == RANGE) {
+                line_current = address.data.range.b;
+            } else if (address.type == SET) {
+                fprintf(stderr, "error: unexpected range addressing\n");
+                break;
+            }
+            printf("%s", lines[line_current]);
+            break;
+        case 'a':
+            handle_append(&address);
+            break;
+        case 'd':
+            handle_delete(&address);
+            break;
+        case 'c':
+            if (!handle_delete(&address)) { break; }
+            address.type = INDEX;
+            address.data.index.i = line_current - 1;
+            handle_append(&address);
+            break;
+        case 'p':
+            if (address.empty && address.data.index.i >= (long int) line_count) {
+                fprintf(stderr, "error: line number %ld does not exist\n", address.data.index.i + 1);
+                break;
+            }
+            if (address.type == INDEX) {
+                printf("%s", lines[address.data.index.i]);
+            } else if (address.type == RANGE) {
+                for (long int i = address.data.range.a; i <= address.data.range.b; i++) {
+                    printf("%s", lines[i]);
+                }
+            } else if (address.type == SET) {
+                for (unsigned long i = 0; i < address.data.set.s; i++) {
+                    printf("%s", lines[address.data.set.b[i]]);
+                }
+            }
+            break;
+        case 'q':
+            if(check_if_sure()) {
+                free_address(address);
+                free_data();
+                exit(EXIT_SUCCESS);
+            };
+            break;
+        case 'Q':
+            free_address(address);
+            free_data();
+            exit(EXIT_SUCCESS);
+        case 'g':
+            skip_whitespace(&index);
+            free_address(address);
+            if (*(index++) != '/') {
+                fprintf(stderr, "error: unexpected character at start or regex\n");
+                break;
+            }
+            if (!parse_regex(&index, &address, ALL)) { return; }
+            for (unsigned long i = 0; i < address.data.set.s; i++) {
+                printf("%s", lines[address.data.set.b[i]]);
+            }
+            break;
+        default:
+            fprintf(stderr, "error: unimplemented command\n");
+            break;
+    }
+
+    free_address(address);
+
+}
+
+static void prompt_loop() {
+    while (true) {
+        prompt();
+    }
+}
+
+COMMAND(ed) {
+    if (argc < 1) {
+        load_empty();
+        prompt_loop();
+    } else {
+        FILE* file = get_file(argv[0], "r");
+        load_file(file);
+        prompt_loop();
+    }
+    return EXIT_SUCCESS;
+}
diff --git a/src/commands/ls.c b/src/commands/ls.c
index b0b00a5..8d64f74 100644
--- a/src/commands/ls.c
+++ b/src/commands/ls.c
@@ -12,12 +12,14 @@
 #include <ftw.h>
 #include <limits.h>
 
-#define FILE_COLOR      "\x1b[0m"
-#define DIR_COLOR       "\x1b[1;34m"
-#define SET_UID_COLOR   "\x1b[41m"
-#define SET_GID_COLOR   "\x1b[43m"
-#define EXEC_COLOR      "\x1b[1;92m"
-#define LINK_COLOR      "\x1b[1;96m"
+#define FILE_COLOR      ANSCII BLACK COLOR
+#define DIR_COLOR       ANSCII BOLD NEXT NORMAL BLUE COLOR
+#define DIR_COLOR_EXEC  ANSCII BACKGROUND GREEN  NEXT NORMAL BLACK COLOR
+#define LINK_COLOR      ANSCII BOLD NEXT HIGHLIGHT TURQUOISE COLOR
+#define SET_UID_COLOR   ANSCII BACKGROUND RED NEXT NORMAL WHITE COLOR
+#define SET_GID_COLOR   ANSCII BACKGROUND YELLOW NEXT NORMAL BLACK COLOR
+#define EXEC_COLOR      ANSCII BOLD NEXT NORMAL GREEN COLOR
+#define BLK_COLOR       ANSCII BOLD NEXT NORMAL YELLOW COLOR
 
 struct Flags {
     bool hidden;
@@ -25,17 +27,17 @@ struct Flags {
     bool more_info;
     bool one_column;
     bool recurse;
-    bool colored;
+    enum When colored;
 };
 
 struct FileInfo {
-    char mode[11];
-    int links;
     struct passwd* usr;
     struct group* grp;
-    char size[5];
-    char date[13];
     char name[PATH_MAX];
+    char date[13];
+    char mode[11];
+    char size[5];
+    int links;
     bool set_uid;
     bool set_gid;
     bool exec;
@@ -76,34 +78,59 @@ static void append_path(char buf[PATH_MAX], const char* dir_path, const char* fi
     buf[dir_len + file_len] = '\0';
 }
 
-static bool get_file_info(struct dirent* file, const char* dir_path, struct FileInfo* info) {
+static bool get_file_info(const char* file_path, const char* dir_path, struct FileInfo* info) {
 
     uid_t uid = getuid();
     gid_t gid = getgid();
 
     char buf[PATH_MAX];
-    append_path(buf, dir_path, file->d_name);
+    append_path(buf, dir_path, file_path);
         
     struct stat s;
     memset(&s, 0, sizeof(struct stat));
 
-    if (stat(buf, &s) < 0) {
-        // printf("\x1b[0merror: failed to read file '%s': %s\n", buf, strerror(errno));
+    if (lstat(buf, &s) < 0) {
+        printf("\x1b[0merror: failed to read file '%s': %s\n", buf, strerror(errno));
         return false;
     }
-
+     
+    int ty = (s.st_mode & S_IFMT) >> 12;
+    
     info->set_uid = false;
     info->set_gid = false;
     info->exec = false;
     info->name[0] = '\0';
 
-    if (file->d_type == DT_DIR) 
-        info->mode[0] = 'd';
-    else if (file->d_type == DT_LNK) 
-        info->mode[0] = 'l';
-    else 
-        info->mode[0] = '-';
-
+    switch (ty) {
+        case DT_BLK:
+            info->mode[0] = 'b';
+            break;
+        case DT_CHR:
+            info->mode[0] = 'c';
+            break;
+        case DT_DIR:
+            info->mode[0] = 'd';
+            break;
+        case DT_FIFO:
+            info->mode[0] = 'f';
+            break;
+        case DT_LNK:
+            info->mode[0] = 'l';
+            break;
+        case DT_SOCK:
+            info->mode[0] = 's';
+            break;
+        case DT_UNKNOWN:
+            info->mode[0] = 'u';
+            break;
+        case DT_WHT:
+            info->mode[0] = 'w';
+            break;
+        default:
+            info->mode[0] = '-';
+            break;
+    }
+    
     info->mode[1] = (s.st_mode & S_IRUSR) ? 'r' : '-';
     info->mode[2] = (s.st_mode & S_IWUSR) ? 'w' : '-';
     if (s.st_mode & S_IXUSR) {
@@ -146,21 +173,31 @@ static bool get_file_info(struct dirent* file, const char* dir_path, struct File
     info->usr = getpwuid(s.st_uid);
     info->grp = getgrgid(s.st_gid);
     info->links = s.st_nlink;
-    info->type = file->d_type;
+    info->type = ty;
 
-    strcpy(info->name, file->d_name);
+    strcpy(info->name, file_path);
 
     print_file_size(s.st_size, info->size);
-    print_date_time(s.st_mtim.tv_sec + s.st_mtim.tv_nsec / 1000000, info->date);
+    print_date_time(s.st_mtim.tv_sec + s.st_mtim.tv_nsec / 1000000000, info->date);
     return true;
 }
 
 static char* get_file_color(struct FileInfo* info) {
     char* color;
     if (info->type == DT_DIR) {
-        color = DIR_COLOR;
+        if (info->mode[8] == 'w') {
+            color = DIR_COLOR_EXEC;
+        } else {
+            color = DIR_COLOR;
+        }
     } else if (info->type == DT_LNK) {
         color = LINK_COLOR;
+    } else if (
+        info->type == DT_CHR || 
+        info->type == DT_BLK ||
+        info->type == DT_SOCK 
+    ) {
+        color = BLK_COLOR;
     } else {
         if (info->set_uid) {
             color = SET_UID_COLOR;
@@ -181,7 +218,8 @@ static void list_files(struct FileInfo* files, int file_len, struct FileListInfo
 
     if (!isatty(1)) {
         flags->one_column = true;
-        flags->colored = false;
+        if (flags->colored == AUTO)
+            flags->colored = NO;
     }
 
     char* color;
@@ -192,7 +230,7 @@ static void list_files(struct FileInfo* files, int file_len, struct FileListInfo
         struct FileInfo finfo = files[i];
         color = get_file_color(&finfo);
         if (flags->more_info) {
-            printf("%s %*d %*s %*s %*s %s %s%s\x1b[0m", 
+            printf("%s %*d %*s %*s %*s %s %s%s%s", 
                 finfo.mode, 
                 info.max_link,
                 finfo.links,
@@ -203,37 +241,40 @@ static void list_files(struct FileInfo* files, int file_len, struct FileListInfo
                 info.max_size,
                 finfo.size, 
                 finfo.date,
-                flags->colored ? color : FILE_COLOR,
-                finfo.name
+                flags->colored != NO ? color : "",
+                finfo.name,
+                flags->colored != NO ? "\x1b[0m" : ""
             );
             if (finfo.type == DT_LNK) {
                 char path[PATH_MAX];
                 append_path(path, dir_path, finfo.name);
 
                 char lnk[PATH_MAX];
-                if (readlink(path, lnk, PATH_MAX) < 0) {
-                    putchar('\n');
+                ssize_t n;
+                if ((n = readlink(path, lnk, PATH_MAX)) != -1) {
+                    printf(" -> %.*s\n", (int)n, lnk);
                 } else {
-                    printf(" -> %s\n", lnk);
+                    putchar('\n');
                 }
             
             } else {
                 putchar('\n');
             }
         } else if (flags->one_column) {
-            printf("%s%s\x1b[0m\n", color, finfo.name);
+            printf("%s%s%s\n", color, finfo.name, flags->colored != NO ? "\x1b[0m" : "");
         } else {
             if (info.total_len > w.ws_col) {
                 if (i != 0 && i % row_count == 0) putchar('\n');
-                printf("%s%*s\x1b[0m", flags->colored ? color : FILE_COLOR, -column_width, finfo.name);
+                printf("%s%*s%s", flags->colored != NO ? color : "", -column_width, 
+                       finfo.name, flags->colored != NO ? "\x1b[0m" : "");
             } else {
-                printf("%s%s\x1b[0m  ", flags->colored ? color : FILE_COLOR, finfo.name);
+                printf("%s%s%s  ", flags->colored != NO ? color : "", finfo.name,
+                       flags->colored != NO ? "\x1b[0m" : "");
             }
         }
     }
 
-    if (info.total_len <= w.ws_col) printf("\n");
-
+    if (!flags->more_info) printf("\n");
 }
 
 static bool is_dot_dir(const char* path) {
@@ -254,25 +295,24 @@ static void push_file(
     struct FileInfo** files, 
     struct FileListInfo* info, 
     int* size, int* capacity, 
-    struct dirent* file, 
+    const char* file_path, 
     const char* dir_path
 ) {
 
     struct FileInfo finfo;
-    if (!get_file_info(file, dir_path, &finfo)) return;
+    if (!get_file_info(file_path, dir_path, &finfo)) return;
 
     if (*size == *capacity) {
         *capacity *= 2;
         *files = realloc(*files, sizeof(struct FileInfo) * *capacity);
     }
-
     int user_len = strlen(finfo.usr->pw_name);
     if (user_len > info->max_usr) info->max_usr = user_len;
 
     int group_len = strlen(finfo.grp->gr_name);
     if (group_len > info->max_grp) info->max_grp = group_len;
 
-    int name_len = strlen(file->d_name);
+    int name_len = strlen(file_path);
     if (name_len > info->max_name) info->max_name = name_len;
 
     int size_len = strlen(finfo.size);
@@ -307,10 +347,13 @@ static bool recurse_directory(char* path, struct Flags* flags) {
         if (!flags->hidden && prefix(".", file->d_name)) continue;
         if (is_dot_dir(file->d_name)) continue;
         if (first) {
-            printf("\n%s%s:%s\n", DIR_COLOR, path, FILE_COLOR);
+            if (flags->colored == NO)
+                printf("\n%s:\n", path);
+            else
+                printf("\n%s%s:%s\n", DIR_COLOR, path, FILE_COLOR);
             first = false;
         }
-        push_file(&files, &info, &size, &capacity, file, path);
+        push_file(&files, &info, &size, &capacity, file->d_name, path);
     }
     
     list_files(files, size, info, flags, path);
@@ -355,16 +398,39 @@ static bool list_directory(char* path, struct Flags* flags) {
     while ((file = readdir(d)) != NULL) {
         if (!flags->hidden && prefix(".", file->d_name)) continue;
         if (flags->hide_dot && is_dot_dir(file->d_name)) continue;
-        push_file(&files, &info, &size, &capacity, file, path);
+        push_file(&files, &info, &size, &capacity, file->d_name, path);
     }
 
-    list_files(files, size, info, flags, path);
+    if (size > 0) list_files(files, size, info, flags, path);
     free(files);
     
     closedir(d);
     return true;
 }
 
+static bool is_dir(const char* path) {
+    struct stat s;
+    if (stat(path, &s) < 0) return false;
+    return S_ISDIR(s.st_mode);
+}
+
+static void list_file_args(int start, int argc, char** argv, struct Flags* flags) {
+    int capacity = 8;
+    int size = 0;
+    struct FileInfo* files = malloc(sizeof(struct FileInfo) * capacity);
+    struct FileListInfo info;
+    memset(&info, 0, sizeof(struct FileListInfo));
+    
+    for (int i = start; i < argc; i++) {
+        if (is_dir(argv[i])) continue;
+        push_file((struct FileInfo**) &files, &info, &size, &capacity, argv[i], ".");
+    }
+    
+    if (size > 0) list_files(files, size, info, flags, ".");
+
+    free(files);
+}
+
 static void help() {
     printf("Usage: ls [FILE]...\n\n");
     printf("List directory contents\n\n");
@@ -384,15 +450,24 @@ COMMAND(ls) {
     flags.hide_dot = false;
     flags.one_column = false;
     flags.recurse = false;
-    flags.colored = false;
+    flags.colored = AUTO;
 
     int start = 0;
     for (int i = 0; i < argc; i++) {
         if (!prefix("-", argv[i])) break;
         if (streql("--help", argv[i])) help();
         start++;
-        if (streql("--color=auto", argv[i]) || streql("--color=yes", argv[i])) {
-            flags.colored = true;
+        if (prefix("--color=", argv[i])) {
+            char* arg = argv[i] + 8;
+            if (streql("yes", arg) || streql("always", arg)) {
+                flags.colored = YES;
+            } else if (streql("auto", arg)) {
+                flags.colored = AUTO;
+            } else if (streql("no", arg) || streql("never", arg)) {
+                flags.colored = NO;
+            } else {
+                error("error: invalid color options: %s", arg);
+            }
             continue;
         }
         for (size_t j = 1; j < strlen(argv[i]); j++) {
@@ -422,14 +497,19 @@ COMMAND(ls) {
 
     if (argc - start == 0) {
         list_directory(".", &flags);
-        if (!flags.more_info) printf("\n");
         return EXIT_SUCCESS;
     }
 
+    list_file_args(start, argc, argv, &flags); 
+
     bool titled = argc - start > 1;
     for (int i = start; i < argc; i++) {
+        if (!is_dir(argv[i])) continue;
         if (titled && !flags.recurse) {
-            printf("\n%s%s:%s\n", DIR_COLOR, argv[i], FILE_COLOR);
+            if (flags.colored != NO) 
+                printf("\n%s%s:%s\n", DIR_COLOR, argv[i], FILE_COLOR);
+            else
+                printf("\n%s:\n", argv[i]);
         }
         if (list_directory(argv[i], &flags) && i + 1 != argc)
             if (titled && !flags.recurse) printf("\n");
diff --git a/src/main.c b/src/main.c
index 72e1531..cd9a81f 100644
--- a/src/main.c
+++ b/src/main.c
@@ -1,4 +1,4 @@
-#include "shared.h"
+#include "util/shared.h"
 #include "command.h"
 
 #include <stdint.h>
@@ -20,7 +20,7 @@ int main (ARGUMENTS) {
         if (argc < 2) {
             printf("usage: lazysphere [function [arguments]...]\n\n");
             printf("currently defined functions:\n");
-            printf("\tdd, cat, yes, echo, printf, id, groups, ls, tail, head\n");
+            printf("\tdd, cat, yes, echo, printf, id, groups, ls, tail, head, ed\n");
             return EXIT_SUCCESS;
         }
         argc--;
@@ -54,6 +54,8 @@ int main (ARGUMENTS) {
         return tail(NEXT_ARGS);
     } else if (streql(cmd, "head")) {
         return head(NEXT_ARGS);
+    } else if (streql(cmd, "ed")) {
+        return ed(NEXT_ARGS);
     } else {
         error("error: invalid command %s", cmd);
     }
diff --git a/src/util/regex.c b/src/util/regex.c
new file mode 100644
index 0000000..58b1f54
--- /dev/null
+++ b/src/util/regex.c
@@ -0,0 +1,528 @@
+/*
+ *
+ * Mini regex-module inspired by Rob Pike's regex code described in:
+ *
+ * http://www.cs.princeton.edu/courses/archive/spr09/cos333/beautiful.html
+ *
+ *
+ *
+ * Supports:
+ * ---------
+ *   '.'        Dot, matches any character
+ *   '^'        Start anchor, matches beginning of string
+ *   '$'        End anchor, matches end of string
+ *   '*'        Asterisk, match zero or more (greedy)
+ *   '+'        Plus, match one or more (greedy)
+ *   '?'        Question, match zero or one (non-greedy)
+ *   '[abc]'    Character class, match if one of {'a', 'b', 'c'}
+ *   '[^abc]'   Inverted class, match if NOT one of {'a', 'b', 'c'} -- NOTE: feature is currently broken!
+ *   '[a-zA-Z]' Character ranges, the character set of the ranges { a-z | A-Z }
+ *   '\s'       Whitespace, \t \f \r \n \v and spaces
+ *   '\S'       Non-whitespace
+ *   '\w'       Alphanumeric, [a-zA-Z0-9_]
+ *   '\W'       Non-alphanumeric
+ *   '\d'       Digits, [0-9]
+ *   '\D'       Non-digits
+ *
+ *
+ */
+
+
+
+#include "regex.h"
+#include <stdio.h>
+#include <ctype.h>
+
+/* Definitions: */
+
+#define MAX_REGEXP_OBJECTS      30    /* Max number of regex symbols in expression. */
+#define MAX_CHAR_CLASS_LEN      40    /* Max length of character-class buffer in.   */
+
+
+enum { UNUSED, DOT, BEGIN, END, QUESTIONMARK, STAR, PLUS, CHAR, CHAR_CLASS, INV_CHAR_CLASS, DIGIT, NOT_DIGIT, ALPHA, NOT_ALPHA, WHITESPACE, NOT_WHITESPACE, /* BRANCH */ };
+
+typedef struct regex_t
+{
+  unsigned char  type;   /* CHAR, STAR, etc.                      */
+  union
+  {
+    unsigned char  ch;   /*      the character itself             */
+    unsigned char* ccl;  /*  OR  a pointer to characters in class */
+  } u;
+} regex_t;
+
+
+
+/* Private function declarations: */
+static int matchpattern(regex_t* pattern, const char* text, int* matchlength);
+static int matchcharclass(char c, const char* str);
+static int matchstar(regex_t p, regex_t* pattern, const char* text, int* matchlength);
+static int matchplus(regex_t p, regex_t* pattern, const char* text, int* matchlength);
+static int matchone(regex_t p, char c);
+static int matchdigit(char c);
+static int matchalpha(char c);
+static int matchwhitespace(char c);
+static int matchmetachar(char c, const char* str);
+static int matchrange(char c, const char* str);
+static int matchdot(char c);
+static int ismetachar(char c);
+
+
+
+/* Public functions: */
+int re_match(const char* pattern, const char* text, int* matchlength)
+{
+  return re_matchp(re_compile(pattern), text, matchlength);
+}
+
+int re_matchp(re_t pattern, const char* text, int* matchlength)
+{
+  *matchlength = 0;
+  if (pattern != 0)
+  {
+    if (pattern[0].type == BEGIN)
+    {
+      return ((matchpattern(&pattern[1], text, matchlength)) ? 0 : -1);
+    }
+    else
+    {
+      int idx = -1;
+
+      do
+      {
+        idx += 1;
+
+        if (matchpattern(pattern, text, matchlength))
+        {
+          if (text[0] == '\0')
+            return -1;
+
+          return idx;
+        }
+      }
+      while (*text++ != '\0');
+    }
+  }
+  return -1;
+}
+
+re_t re_compile(const char* pattern)
+{
+  /* The sizes of the two static arrays below substantiates the static RAM usage of this module.
+     MAX_REGEXP_OBJECTS is the max number of symbols in the expression.
+     MAX_CHAR_CLASS_LEN determines the size of buffer for chars in all char-classes in the expression. */
+  static regex_t re_compiled[MAX_REGEXP_OBJECTS];
+  static unsigned char ccl_buf[MAX_CHAR_CLASS_LEN];
+  int ccl_bufidx = 1;
+
+  char c;     /* current char in pattern   */
+  int i = 0;  /* index into pattern        */
+  int j = 0;  /* index into re_compiled    */
+
+  while (pattern[i] != '\0' && (j+1 < MAX_REGEXP_OBJECTS))
+  {
+    c = pattern[i];
+
+    switch (c)
+    {
+      /* Meta-characters: */
+      case '^': {    re_compiled[j].type = BEGIN;           } break;
+      case '$': {    re_compiled[j].type = END;             } break;
+      case '.': {    re_compiled[j].type = DOT;             } break;
+      case '*': {    re_compiled[j].type = STAR;            } break;
+      case '+': {    re_compiled[j].type = PLUS;            } break;
+      case '?': {    re_compiled[j].type = QUESTIONMARK;    } break;
+/*    case '|': {    re_compiled[j].type = BRANCH;          } break; <-- not working properly */
+
+      /* Escaped character-classes (\s \w ...): */
+      case '\\':
+      {
+        if (pattern[i+1] != '\0')
+        {
+          /* Skip the escape-char '\\' */
+          i += 1;
+          /* ... and check the next */
+          switch (pattern[i])
+          {
+            /* Meta-character: */
+            case 'd': {    re_compiled[j].type = DIGIT;            } break;
+            case 'D': {    re_compiled[j].type = NOT_DIGIT;        } break;
+            case 'w': {    re_compiled[j].type = ALPHA;            } break;
+            case 'W': {    re_compiled[j].type = NOT_ALPHA;        } break;
+            case 's': {    re_compiled[j].type = WHITESPACE;       } break;
+            case 'S': {    re_compiled[j].type = NOT_WHITESPACE;   } break;
+
+            /* Escaped character, e.g. '.' or '$' */
+            default:
+            {
+              re_compiled[j].type = CHAR;
+              re_compiled[j].u.ch = pattern[i];
+            } break;
+          }
+        }
+        /* '\\' as last char in pattern -> invalid regular expression. */
+/*
+        else
+        {
+          re_compiled[j].type = CHAR;
+          re_compiled[j].ch = pattern[i];
+        }
+*/
+      } break;
+
+      /* Character class: */
+      case '[':
+      {
+        /* Remember where the char-buffer starts. */
+        int buf_begin = ccl_bufidx;
+
+        /* Look-ahead to determine if negated */
+        if (pattern[i+1] == '^')
+        {
+          re_compiled[j].type = INV_CHAR_CLASS;
+          i += 1; /* Increment i to avoid including '^' in the char-buffer */
+          if (pattern[i+1] == 0) /* incomplete pattern, missing non-zero char after '^' */
+          {
+            return 0;
+          }
+        }
+        else
+        {
+          re_compiled[j].type = CHAR_CLASS;
+        }
+
+        /* Copy characters inside [..] to buffer */
+        while (    (pattern[++i] != ']')
+                && (pattern[i]   != '\0')) /* Missing ] */
+        {
+          if (pattern[i] == '\\')
+          {
+            if (ccl_bufidx >= MAX_CHAR_CLASS_LEN - 1)
+            {
+              //fputs("exceeded internal buffer!\n", stderr);
+              return 0;
+            }
+            if (pattern[i+1] == 0) /* incomplete pattern, missing non-zero char after '\\' */
+            {
+              return 0;
+            }
+            ccl_buf[ccl_bufidx++] = pattern[i++];
+          }
+          else if (ccl_bufidx >= MAX_CHAR_CLASS_LEN)
+          {
+              //fputs("exceeded internal buffer!\n", stderr);
+              return 0;
+          }
+          ccl_buf[ccl_bufidx++] = pattern[i];
+        }
+        if (ccl_bufidx >= MAX_CHAR_CLASS_LEN)
+        {
+            /* Catches cases such as [00000000000000000000000000000000000000][ */
+            //fputs("exceeded internal buffer!\n", stderr);
+            return 0;
+        }
+        /* Null-terminate string end */
+        ccl_buf[ccl_bufidx++] = 0;
+        re_compiled[j].u.ccl = &ccl_buf[buf_begin];
+      } break;
+
+      /* Other characters: */
+      default:
+      {
+        re_compiled[j].type = CHAR;
+        re_compiled[j].u.ch = c;
+      } break;
+    }
+    /* no buffer-out-of-bounds access on invalid patterns - see https://github.com/kokke/tiny-regex-c/commit/1a279e04014b70b0695fba559a7c05d55e6ee90b */
+    if (pattern[i] == 0)
+    {
+      return 0;
+    }
+
+    i += 1;
+    j += 1;
+  }
+  /* 'UNUSED' is a sentinel used to indicate end-of-pattern */
+  re_compiled[j].type = UNUSED;
+
+  return (re_t) re_compiled;
+}
+
+void re_print(regex_t* pattern)
+{
+  const char* types[] = { "UNUSED", "DOT", "BEGIN", "END", "QUESTIONMARK", "STAR", "PLUS", "CHAR", "CHAR_CLASS", "INV_CHAR_CLASS", "DIGIT", "NOT_DIGIT", "ALPHA", "NOT_ALPHA", "WHITESPACE", "NOT_WHITESPACE", "BRANCH" };
+
+  int i;
+  int j;
+  char c;
+  for (i = 0; i < MAX_REGEXP_OBJECTS; ++i)
+  {
+    if (pattern[i].type == UNUSED)
+    {
+      break;
+    }
+
+    printf("type: %s", types[pattern[i].type]);
+    if (pattern[i].type == CHAR_CLASS || pattern[i].type == INV_CHAR_CLASS)
+    {
+      printf(" [");
+      for (j = 0; j < MAX_CHAR_CLASS_LEN; ++j)
+      {
+        c = pattern[i].u.ccl[j];
+        if ((c == '\0') || (c == ']'))
+        {
+          break;
+        }
+        printf("%c", c);
+      }
+      printf("]");
+    }
+    else if (pattern[i].type == CHAR)
+    {
+      printf(" '%c'", pattern[i].u.ch);
+    }
+    printf("\n");
+  }
+}
+
+
+
+/* Private functions: */
+static int matchdigit(char c)
+{
+  return isdigit(c);
+}
+static int matchalpha(char c)
+{
+  return isalpha(c);
+}
+static int matchwhitespace(char c)
+{
+  return isspace(c);
+}
+static int matchalphanum(char c)
+{
+  return ((c == '_') || matchalpha(c) || matchdigit(c));
+}
+static int matchrange(char c, const char* str)
+{
+  return (    (c != '-')
+           && (str[0] != '\0')
+           && (str[0] != '-')
+           && (str[1] == '-')
+           && (str[2] != '\0')
+           && (    (c >= str[0])
+                && (c <= str[2])));
+}
+static int matchdot(char c)
+{
+#if defined(RE_DOT_MATCHES_NEWLINE) && (RE_DOT_MATCHES_NEWLINE == 1)
+  (void)c;
+  return 1;
+#else
+  return c != '\n' && c != '\r';
+#endif
+}
+static int ismetachar(char c)
+{
+  return ((c == 's') || (c == 'S') || (c == 'w') || (c == 'W') || (c == 'd') || (c == 'D'));
+}
+
+static int matchmetachar(char c, const char* str)
+{
+  switch (str[0])
+  {
+    case 'd': return  matchdigit(c);
+    case 'D': return !matchdigit(c);
+    case 'w': return  matchalphanum(c);
+    case 'W': return !matchalphanum(c);
+    case 's': return  matchwhitespace(c);
+    case 'S': return !matchwhitespace(c);
+    default:  return (c == str[0]);
+  }
+}
+
+static int matchcharclass(char c, const char* str)
+{
+  do
+  {
+    if (matchrange(c, str))
+    {
+      return 1;
+    }
+    else if (str[0] == '\\')
+    {
+      /* Escape-char: increment str-ptr and match on next char */
+      str += 1;
+      if (matchmetachar(c, str))
+      {
+        return 1;
+      }
+      else if ((c == str[0]) && !ismetachar(c))
+      {
+        return 1;
+      }
+    }
+    else if (c == str[0])
+    {
+      if (c == '-')
+      {
+        return ((str[-1] == '\0') || (str[1] == '\0'));
+      }
+      else
+      {
+        return 1;
+      }
+    }
+  }
+  while (*str++ != '\0');
+
+  return 0;
+}
+
+static int matchone(regex_t p, char c)
+{
+  switch (p.type)
+  {
+    case DOT:            return matchdot(c);
+    case CHAR_CLASS:     return  matchcharclass(c, (const char*)p.u.ccl);
+    case INV_CHAR_CLASS: return !matchcharclass(c, (const char*)p.u.ccl);
+    case DIGIT:          return  matchdigit(c);
+    case NOT_DIGIT:      return !matchdigit(c);
+    case ALPHA:          return  matchalphanum(c);
+    case NOT_ALPHA:      return !matchalphanum(c);
+    case WHITESPACE:     return  matchwhitespace(c);
+    case NOT_WHITESPACE: return !matchwhitespace(c);
+    default:             return  (p.u.ch == c);
+  }
+}
+
+static int matchstar(regex_t p, regex_t* pattern, const char* text, int* matchlength)
+{
+  int prelen = *matchlength;
+  const char* prepoint = text;
+  while ((text[0] != '\0') && matchone(p, *text))
+  {
+    text++;
+    (*matchlength)++;
+  }
+  while (text >= prepoint)
+  {
+    if (matchpattern(pattern, text--, matchlength))
+      return 1;
+    (*matchlength)--;
+  }
+
+  *matchlength = prelen;
+  return 0;
+}
+
+static int matchplus(regex_t p, regex_t* pattern, const char* text, int* matchlength)
+{
+  const char* prepoint = text;
+  while ((text[0] != '\0') && matchone(p, *text))
+  {
+    text++;
+    (*matchlength)++;
+  }
+  while (text > prepoint)
+  {
+    if (matchpattern(pattern, text--, matchlength))
+      return 1;
+    (*matchlength)--;
+  }
+
+  return 0;
+}
+
+static int matchquestion(regex_t p, regex_t* pattern, const char* text, int* matchlength)
+{
+  if (p.type == UNUSED)
+    return 1;
+  if (matchpattern(pattern, text, matchlength))
+      return 1;
+  if (*text && matchone(p, *text++))
+  {
+    if (matchpattern(pattern, text, matchlength))
+    {
+      (*matchlength)++;
+      return 1;
+    }
+  }
+  return 0;
+}
+
+
+#if 0
+
+/* Recursive matching */
+static int matchpattern(regex_t* pattern, const char* text, int *matchlength)
+{
+  int pre = *matchlength;
+  if ((pattern[0].type == UNUSED) || (pattern[1].type == QUESTIONMARK))
+  {
+    return matchquestion(pattern[1], &pattern[2], text, matchlength);
+  }
+  else if (pattern[1].type == STAR)
+  {
+    return matchstar(pattern[0], &pattern[2], text, matchlength);
+  }
+  else if (pattern[1].type == PLUS)
+  {
+    return matchplus(pattern[0], &pattern[2], text, matchlength);
+  }
+  else if ((pattern[0].type == END) && pattern[1].type == UNUSED)
+  {
+    return text[0] == '\0';
+  }
+  else if ((text[0] != '\0') && matchone(pattern[0], text[0]))
+  {
+    (*matchlength)++;
+    return matchpattern(&pattern[1], text+1);
+  }
+  else
+  {
+    *matchlength = pre;
+    return 0;
+  }
+}
+
+#else
+
+/* Iterative matching */
+static int matchpattern(regex_t* pattern, const char* text, int* matchlength)
+{
+  int pre = *matchlength;
+  do
+  {
+    if ((pattern[0].type == UNUSED) || (pattern[1].type == QUESTIONMARK))
+    {
+      return matchquestion(pattern[0], &pattern[2], text, matchlength);
+    }
+    else if (pattern[1].type == STAR)
+    {
+      return matchstar(pattern[0], &pattern[2], text, matchlength);
+    }
+    else if (pattern[1].type == PLUS)
+    {
+      return matchplus(pattern[0], &pattern[2], text, matchlength);
+    }
+    else if ((pattern[0].type == END) && pattern[1].type == UNUSED)
+    {
+      return (text[0] == '\0');
+    }
+/*  Branching is not working properly
+    else if (pattern[1].type == BRANCH)
+    {
+      return (matchpattern(pattern, text) || matchpattern(&pattern[2], text));
+    }
+*/
+  (*matchlength)++;
+  }
+  while ((text[0] != '\0') && matchone(*pattern++, *text++));
+
+  *matchlength = pre;
+  return 0;
+}
+
+#endif
diff --git a/src/util/regex.h b/src/util/regex.h
new file mode 100644
index 0000000..69facc6
--- /dev/null
+++ b/src/util/regex.h
@@ -0,0 +1,65 @@
+/*
+ *
+ * Mini regex-module inspired by Rob Pike's regex code described in:
+ *
+ * http://www.cs.princeton.edu/courses/archive/spr09/cos333/beautiful.html
+ *
+ *
+ *
+ * Supports:
+ * ---------
+ *   '.'        Dot, matches any character
+ *   '^'        Start anchor, matches beginning of string
+ *   '$'        End anchor, matches end of string
+ *   '*'        Asterisk, match zero or more (greedy)
+ *   '+'        Plus, match one or more (greedy)
+ *   '?'        Question, match zero or one (non-greedy)
+ *   '[abc]'    Character class, match if one of {'a', 'b', 'c'}
+ *   '[^abc]'   Inverted class, match if NOT one of {'a', 'b', 'c'} -- NOTE: feature is currently broken!
+ *   '[a-zA-Z]' Character ranges, the character set of the ranges { a-z | A-Z }
+ *   '\s'       Whitespace, \t \f \r \n \v and spaces
+ *   '\S'       Non-whitespace
+ *   '\w'       Alphanumeric, [a-zA-Z0-9_]
+ *   '\W'       Non-alphanumeric
+ *   '\d'       Digits, [0-9]
+ *   '\D'       Non-digits
+ *
+ *
+ */
+
+#ifndef _TINY_REGEX_C
+#define _TINY_REGEX_C
+
+
+#ifndef RE_DOT_MATCHES_NEWLINE
+/* Define to 0 if you DON'T want '.' to match '\r' + '\n' */
+#define RE_DOT_MATCHES_NEWLINE 1
+#endif
+
+#ifdef __cplusplus
+extern "C"{
+#endif
+
+
+
+/* Typedef'd pointer to get abstract datatype. */
+typedef struct regex_t* re_t;
+
+
+/* Compile regex string pattern to a regex_t-array. */
+re_t re_compile(const char* pattern);
+
+
+/* Find matches of the compiled pattern inside text. */
+int re_matchp(re_t pattern, const char* text, int* matchlength);
+
+
+/* Find matches of the txt pattern inside text (will compile automatically first). */
+int re_match(const char* pattern, const char* text, int* matchlength);
+
+
+#ifdef __cplusplus
+}
+#endif
+
+#endif /* ifndef _TINY_REGEX_C */
diff --git a/src/shared.c b/src/util/shared.c
index 240e364..c5c22e9 100644
--- a/src/shared.c
+++ b/src/util/shared.c
@@ -18,15 +18,19 @@ void error(const char* format, ...) {
 
 FILE* get_file_s(const char* path, const char* type) {
     struct stat s;
-    if (stat(path, &s) < 0) {
+    if (lstat(path, &s) < 0) {
+        if (type[0] != 'r') goto read;
         fprintf(stderr, "error: failed to read %s: %s\n", path, strerror(errno));
         return NULL;
     }
-    if (!S_ISREG(s.st_mode)) {
-        fprintf(stderr, "error: %s is not a file\n", path);
+    if (S_ISDIR(s.st_mode)) {
+        fprintf(stderr, "error: %s is a directory\n", path);
         return NULL;
     }
-    FILE* file = fopen(path, type);
+
+    FILE* file;
+read:
+    file = fopen(path, type);
     if (file == NULL) {
         fprintf(stderr, "error: failed to open file %s: %s\n", path, strerror(errno));
     }
@@ -34,7 +38,10 @@ FILE* get_file_s(const char* path, const char* type) {
 }
 
 FILE* get_file(const char* path, const char* type) {
-    if (streql("-", path)) return stdin;
+    if (streql("-", path) && type[0] == 'r') {
+        clearerr(stdin);
+        return stdin;
+    }
     FILE* file = get_file_s(path, type);
     if (file == NULL) exit(EXIT_FAILURE);
     return file;
diff --git a/src/shared.h b/src/util/shared.h
index a542ba6..5e5f4a9 100644
--- a/src/shared.h
+++ b/src/util/shared.h
@@ -4,6 +4,33 @@
 #include <stdbool.h>
 #include <time.h>
 
+#define ANSCII          "\x1b["
+#define NEXT            ";"
+
+#define RESET           "0"
+#define BOLD            "1"
+
+#define NORMAL          "3"
+#define BACKGROUND      "4"
+#define HIGHLIGHT       "9"
+
+#define BLACK           "0"
+#define RED             "1"
+#define GREEN           "2"
+#define YELLOW          "3"
+#define BLUE            "4"
+#define MAGENTA         "5"
+#define TURQUOISE       "6"
+#define WHITE           "7"
+
+#define COLOR           "m"
+
+enum When {
+    YES,
+    NO,
+    AUTO
+};
+
 __attribute__ ((__format__(printf, 1, 2)))
 void error(const char* format, ...);