Merge pull request #8 from elenammul/patch-4

Exercise.004.solutions

Author: rascasoft

MMUL-BASH-01/Exercises/Day-2/Exercise.004.solutions

@@ -0,0 +1,50 @@
+# Exercise 004 - Playing with file permissions - Solutions
+
+1) Create a file called testfile1 in your home dir
+
+[mmul@localhost ~]$ mkdir /tmp/scratch
+[mmul@localhost ~]$ cd /tmp/scratch/
+[mmul@localhost scratch]$ touch testfile1
+
+2) Check permissions, remove all permission on the file except for owner
+
+[mmul@localhost scratch]$ ls -l
+-rw-rw-r-- 1 mmul mmul 0 Dec  2 16:33 testfile1
+
+[mmul@localhost scratch]$ chmod 0600 testfile1
+
+[mmul@localhost ~]$ ls -l
+-rw------- 2 mmul mmul 60 Dec  2 16:33 testfile1
+
+3) Switching account and trying to remove file testfile1
+
+[mmul@localhost scratch]$ su - mmul2
+
+[mmul@localhost scratch]$ cd /tmp/scratch
+
+[mmul2@localhost scratch]$ rm testfile1
+rm: remove write-protected regular empty file 'testfile1'? y
+rm: cannot remove 'testfile1': Permission denied
+
+4) Re-assign permissions
+
+[mmul@localhost scratch]$ chmod 0777 testfile1
+
+[mmul@localhost scratch]$ ls -l
+-rwxrwxrwx 1 mmul mmul 0 Dec  2 16:41 testfile1
+
+5) Trying to remove again
+
+[mmul2@localhost scratch]$ ls -l
+-rwxrwxrwx 1 mmul mmul 0 Dec  2 16:41 testfile1
+
+[mmul2@localhost scratch]$ rm testfile1
+rm: cannot remove 'testfile1': Permission denied
+
+6) Check /tmp permissions
+
+[mmul2@localhost scratch]$ ls -ld /tmp/
+drwxrwxrwt 34 root root 1720 Dec  2 17:00 /tmp/
+
+/tmp has the sticky bit enabled! This means that, despite the full access, 
+we cannot remove testfile1 because mmul2 is not the owner.