dirname: implementation of the dirname command

Makefile

@@ -29,6 +29,8 @@ all:
 	@make -C rm
 	@echo "\x1B[0;1;35m make\x1B[0m utilities/ln"
 	@make -C ln
+	@echo "\x1B[0;1;35m make\x1B[0m utilities/dirname"
+	@make -C dirname
 
 install:
 	@mkdir -p out
@@ -62,6 +64,8 @@ install:
 	@make install -C rm
 	@echo "\x1B[0;1;35m make\x1B[0m install utilities/ln"
 	@make install -C ln
+	@echo "\x1B[0;1;35m make\x1B[0m install utilities/dirname"
+	@make install -C dirname
 
 clean:
 	@echo "\x1B[0;1;35m make\x1B[0m clean utilities/hello"
@@ -93,4 +97,6 @@ clean:
 	@echo "\x1B[0;1;35m make\x1B[0m clean utilities/rm"
 	@make clean -C rm
 	@echo "\x1B[0;1;35m make\x1B[0m clean utilities/ln"
-	@make clean -C ln
+	@make clean -C ln
+	@echo "\x1B[0;1;35m make\x1B[0m clean utilities/dirname"
+	@make clean -C dirname

dirname/Makefile

@@ -0,0 +1,23 @@
+PLATFORM=x86_64-lux
+CCFLAGS=-Wall -c -O3
+LDFLAGS=-llux
+CC=x86_64-lux-gcc
+LD=x86_64-lux-gcc
+SRC:=$(shell find . -type f -name "*.c")
+OBJ:=$(SRC:.c=.o)
+
+all: dirname
+
+%.o: %.c
+	@echo "\x1B[0;1;32m cc  \x1B[0m $<"
+	@$(CC) $(CCFLAGS) -o $@ $<
+
+dirname: $(OBJ)
+	@echo "\x1B[0;1;93m ld  \x1B[0m dirname"
+	@$(LD) $(OBJ) -o dirname $(LDFLAGS)
+
+install: dirname
+	@cp dirname ../out/
+
+clean:
+	@rm -f dirname $(OBJ)

dirname/dirname.c

@@ -0,0 +1,63 @@
+/*
+ * luxOS - a unix-like operating system
+ * Omar Elghoul, 2024-25
+ * 
+ * dirname: Implementation of the dirname command
+ */
+
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+#include <limits.h>
+
+int main(int argc, char **argv) {
+    if(argc < 2) {
+        fprintf(stderr, "usage: %s string...\n", argv[0]);
+        return EXIT_FAILURE;
+    }
+
+    char new[PATH_MAX];
+    const char *old;
+
+    for(int i = 1; i < argc; i++) {
+        old = argv[i];
+        memset(new, 0, PATH_MAX);
+
+        if((strlen(old) == 1) && (old[0] == '/')) {
+            new[0] = '/';
+            goto print;
+        }
+
+        if((strlen(old) == 2) && (old[0] == '/') && (old[1] == '/')) {
+            new[0] = '/';
+            goto print;
+        }
+
+        strcpy(new, old);
+
+        for(int j = strlen(new)-1; j >= 0; j--) {
+            if(new[j] == '/') new[j] = 0;
+            else break;
+        }
+
+        if(!strchr(new, '/')) {
+            sprintf(new, ".");
+            goto print;
+        }
+
+        for(int j = strlen(new)-1; j >= 0; j--) {
+            if(new[j] != '/') new[j] = 0;
+            else {
+                new[j] = 0;
+                break;
+            }
+        }
+
+        if(!strlen(new)) sprintf(new, "/");
+
+print:
+        printf("%s\n", new);
+    }
+
+    return EXIT_SUCCESS;
+}